Giant Costco Copycat Gluten Free Zucchini Muffins

Zucchini has been my ultimate veggie staple since sixth grade. Weird? Maybe. Sixth grade was a bumpy year: I was homeschooled that year because it was the *YEAR OF THE TESTS* – ie tons of medical stuff going on to figure out what the heck was wrong with me, why I had stopped growing, couldn’t gain weight, and had stomach issues constantly. Cue Celiac Diagnosis *enters stage right* – and that solved it! But before the diagnosis my mom was doing TONS of research to try and track down tests or diets or other dietary ideas that might alleviate my symptoms. We did a few months with no sugar or grains. THAT was a nightmare as an 11 year old. But it forced me to really dive into cooking for myself and eating more veggies + protein (which I sorely needed anyway). I would regularly have sautéed zucchini and ground turkey or cheese for breakfast. Sounds bizarre but I fell in LOVE with zucchini. Long story long, here we are in the midst of our continued GIANT muffin saga and I of course needed to highlight my lifelong veggie pal: zucchini. So here are the BEST ever gluten free zucchini muffins for your enjoyment (and mine – I’ve eaten two today). Note to all – this is a family recipe – by my mother and with a little input from me and Kendra, that she’s shared with us and allowed us to share here. Keep hold of those family recipes, y’all!! They’re worth their weight in muffins.

Back to the giant muffins! So far we’ve made these giant poppyseed muffins, giant blueberry muffins, giant chocolate chip muffins, giant double chocolate muffins, giant banana nut muffins, giant strawberry rhubarb muffins, giant apple streusel muffins, these giant lemon raspberry muffins, giant cherry chocolate chip muffins, these giant coffee walnut muffins, these giant pistachio apricot muffins, and these giant orange marmalade muffins!

Tips for the Most Awesome Giant Zucchini Muffins:

A few tips for getting these to turn out just like you remember those Costco muffins:

• Use the right-size of pan! Apparently, Costco keeps their giant muffin pans as a trade secret because we can’t find them ANYWHERE on the internet and you can find EVERYTHING on the internet. Bravo, Costco, for a secret well-kept. However, we’ve found a way to crack the code and gone ahead and just used these brilliant 4-inch cake pans because, after careful inspection, we’ve discovered that Costco muffins are exactly 4-inches in diameter! HA! Take that, Costco-bakery-lords. I never thought I’d be regularly using 4-inch cake pans but here we are. I’ll just need to make a bunch of tiny cake recipes next!
• Pack in that zucchini! Don’t skimp on the amount of grated zucchini you use – be sure to press it down in the measuring cup to get all those veggies!
• Let your batter REST, per the recipe, for at least 30 minutes. For two reasons: 1) the batter thickens as it rests; and 2) something somewhere said that baking powder needs a bit more time to “activate.” Don’t quote me on this, who knows if it’s actually true.
• Don’t over-mix your batter! Muffins need a lot of lift, especially these giant ones, and if you over-mix your batter, you’ll end up with flat or sunken muffins which is no fun.
• Use a good 1-1 gluten free flour mix! We use the Bob’s Red Mill one (the baking mix), though we’ve heard good things about Cup-4-Cup. We’ve only tested this recipe with this one so if you want them to turn out exactly like ours, we recommend snagging a bag of that specific 1-1 gluten free flour.
• Do NOT open the oven door during baking time. Tape it shut if you have to! You can certainly turn on the oven light and peek and the gloriousness that is a set of rising muffins nearly-ready to be devoured, but do not open that door! Opening the door will immediately lower the oven temp and prohibit your muffins from rising correctly. If you’re in the last few minutes of baking and need to test to see if they’re done, open the oven just a tiny bit and reach in and just tap the top of one – if it springs back it’s done, if it presses in like a foam mattress topper, it’s not and needs a couple more minutes!
• These will keep in an airtight container (or in ziplock baggies) for a week or so – and they freeze REALLY well! So if you want to make a batch and save a bunch, put them in a sturdy plastic container or a freezer plastic bag and pop them in there. Then microwave for about 30-45 seconds (from frozen) before eating! I even like popping mine in the microwave for 10-15 seconds from room temp to get them all warm and floofy again before eating.
• GLAZE: glazes are a super easy way to elevate your muffin game. The glazes we use are essentially just powdered sugar and a liquid – in this case, milk and melted butter. The key with glazes is getting the consistency right – you want to be able to drizzle or pour the glaze, so it needs to be able to move a bit, but you don’t want it to just pour off your muffins completely. You want to get to a thicker consistency (it should be thick when you stir it), that slowly pours when you lift up your stirring spoon. This will ensure that your glaze stays mostly on top of the muffin and that it stays opaque and doesn’t run off in a giant puddle. If your glaze seems to thin and runny, just add more powdered sugar! Vice versa if it seems waaaay too thick and you can’t even get it to pour, add a touch more milk.

Print Recipe

Giant Gluten Free Zucchini Muffins

These giant fluffy zucchini muffins are packed with cinnamon, vanilla, and zucchini – and topped with a cinnamon glaze!

Prep Time25 minutes mins

Cook Time45 minutes mins

Resting time30 minutes mins

Course: Breakfast, Snack

Cuisine: American

Diet: Gluten Free

Keyword: breakfast, costco muffins, easy, giant, glaze, gluten free, healthy, muffins, simple, zucchini

Servings: 6 giant muffins

Calories: 550kcal

Author: Amelia Farber

Equipment

• Six 4-inch cake pans (link below to the ones we use)
• Cookie sheet

Ingredients

For the muffins:

• 3 large eggs
• 1/2 Cup canola oil
• 1/2 Cup browned salted butter instructions below – start with 2/3 cup of salted butter!
• 3/4 Cup white sugar
• 3/4 Cup packed brown sugar
• 1 Tbsp vanilla extract
• 3 Cups gluten free 1-1 flour mix link below to the one we use – with xanthan gum included (if your mix does not have xanthan gum, add 1 teaspoon of it now)
• 3 1/2 tsp ground cinnamon
• 1/4 tsp ground nutmeg
• 2 1/2 tsp baking powder
• 1/2 tsp baking soda
• 3/4 tsp salt
• 3 Cups packed grated zucchini don't squeeze out the water
• 1 1/2 Cups chopped raw walnuts optional

For the glaze

• 1 1/4 Cup sifted powdered sugar
• 1-2 Tbsp milk
• 1 tsp melted butter
• 1 tsp ground cinnamon
• 1/4 tsp vanilla extract

Instructions

• First, make your browned butter! In a small saucepan over medium-low heat, melt the 3/4 cup of salted butter and stir constantly until melted and simmering. Continue to simmer, on medium heat, for at least a few minutes, until the popping and hissing sounds have completely subsided (this is the water in the butter burning off – you’ll know once it’s silent). Continue to cook, stirring constantly, until the butter reaches a deep amber color and smells nutty or caramelly. The butter may foam, so keep stirring/lifting up spoonfuls of the butter to see the color. The browned milk solids will foam up in the center of the pan – once it does that- immediately take off the burner and let sit for a few minutes, then pour (scrape ALL of the brown bits – that's the flavor!) into a heat-proof small bowl and let it cool to just above room temp (still liquid).
• Once your browned butter is cooled but still liquid, make your muffin batter! It will need to rest for 30 minutes before baking. In a large bowl, whisk together the eggs, sugar (white and brown), oil, melted cooled browned butter (you'll end up with about 1/2 cup of browned butter), and vanilla. Then stir in the gluten free 1-1 flour mix, baking powder, baking soda, cinnamon, nutmeg, and salt. Finally, fold in the three packed cups of grated zucchini and the 1 1/2 cups of chopped walnuts until just combined. Do not over-mix or your muffins won't rise. Let the batter sit at room temp for 30 minutes.
• Finally, preheat the oven to 350° Fahrenheit and place your six 4-inch cake pans on a cookie sheet. Spray each pan with cooking spray, then spoon batter into each one evenly (they should be about 2/3-3/4 full). Bake for 40-45 minutes until the tops spring back with touched (do NOT open the oven while baking or the muffins will deflate. To check if done, open the oven only once very little and tap muffin with your finger). Let cool nearly-completely before turning out and glazing.
• While the muffins are cooling, make the glaze! In a medium cereal bowl, stir together all of the glaze ingredients (start with 1 Tbsp of milk and then add more if needed) until smooth – this will take some working. Check the consistency of the glaze: you're looking for a glaze that can drizzle over the muffins, but doesn't flow too quickly or it will simply run off and not hold on top of the muffins. Add more powdered sugar if it seems too thin/runny. Once it's a pourable consistency, drizzle over your muffins!
• You can let the glazed muffins sit at room temp for 30-45 minutes for the glaze to harden, then put into zip-top bags and keep in the fridge or freezer for up to a week. Best-served slightly warm, so pop them in the microwave for 10-20 seconds from room temp!

Tag @sisterssansgluten on Instagram if you snap a photo of your muffins!

Food photography and styling by Amelia Farber