Giant Gluten Free Costco Copycat Blackberry Nectarine Crumble Muffins
These muffins are like your favorite summer crisp or crumble in muffin form: packed with oats, fresh blackberries and nectarines, with an oat crumble topping and blackberry glaze
Servings: 6 giant muffins
Calories: 550kcal
Equipment
- Six 4-inch round cake pans (link below to the ones we use)
- Cookie sheet
Ingredients
For the crumble topping:
- 5 Tbsp salted butter melted
- 1/2 Cup plus 2 Tbsp gluten free 1-1 flour mix with xanthan gum added (if it doesn't have xanthan gum, add 1/8 teaspoon xanthan gum)
- 1/2 Cup quick cooking gluten free oats
- 1/4 Cup packed brown sugar
- 1/4 tsp ground cinnamon
- 1/4 tsp ground ginger
- pinch nutmeg
- pinch salt
- 1/8 tsp vanilla extract
- 1 Tbsp blanched almond flour
For the muffins:
- 4 large eggs
- 1 Cup white sugar
- 1/2 Cup packed brown sugar
- 1/2 Cup canola oil
- 1/2 Cup browned salted butter - start with 2/3 cup butter then brown it instructions below
- 1 Cup milk
- 1/2 Cup sour cream
- 3 tsp vanilla extract
- 2 Cups gluten free 1-1 flour mix with xanthan gum added (if it doesn't have xanthan gum, add 1 teaspoon xanthan gum)
- 1 1/2 Cups gluten free rolled oats not quick cooking
- 1/2 Cup packed blanched almond flour
- 1/4 Cup sweet rice flour
- 1/4 Cup arrowroot starch
- 1/4 tsp cinnamon
- 1/4 tsp ginger
- 1/8 tsp nutmeg
- 2 3/4 tsp baking powder
- 3/4 tsp salt
- 2 Cups fresh blackberries chopped in half
- 2 Cups chopped fresh nectarines 1/2 inch pieces
For the blackberry glaze:
- 1 1/4 Cup sifted powdered sugar
- 1/4 Cup strained fresh blackberry puree
- 1 tsp lemon juice
- 1 tsp melted salted butter
- pinch ginger, nutmeg, cinnamon, salt
Instructions
- First, make your browned butter! In a small saucepan over medium-low heat, melt the 2/3 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 (but not solid).
- While the browned butter is cooling, make the crumble topping. In a medium bowl, combine all of the crumble topping ingredients (the flour, quick oats, butter spices, brown sugar, vanilla, salt, almond flour), mixing together until all of the flour has been combined and there is no extra white/floury/oat bits. Then start crumbling the mixture into smaller chunks (1/4-1/2 inch chunks) and then let the crumble sit while you make the muffin batter.
- Then, make the muffin batter! It will need to rest at room temp for 30 minutes before baking. In a large bowl, whisk together the eggs, sugars, oil, melted but cooled browned butter (it should be about 1/2 cup now), milk, sour cream, and vanilla extract until thicker and smooth. Add in the gluten free 1-1 flour, gluten free rolled oats, gluten free sweet rice flour, arrowroot starch, almond flour, spices, baking powder, and salt and whisk until totally combined and smooth. Then fold in the chopped blackberries and nectarines (no need to peel them) then let the batter sit either on the counter for at least 30 minutes before baking (you can let it rest in the fridge for longer if you want).
- Once the batter has rested preheat the oven to 425° 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 3/4-5/6 full) and then top each muffin with a generous amount of the crumble topping - completely covering each muffin. Bake for 5 minutes at 425 then immediately lower the temp to 350° F (do NOT open the oven door!) and let bake for 35-40 more minutes until the tops spring back with touched. Let cool nearly-completely before turning out.
- Once the muffins are nearly-cooled and have been turned out (carefully or all the topping will crumble off!) onto a tray or plate, make your glaze! In a smaller bowl, stir together all of the glaze ingredients with a table spoon until you reach the right consistency. You're looking for fairly thick glaze that you can still pour or drizzle but that pours slowly so that it will stay on top of the muffins and not run off. If the glaze is too thick, add a touch more liquid like lemon juice or blackberry puree (strained); if it's too thin, add more sifted powdered sugar. Then drizzle the glaze generously over the top of each muffin, and then serve!
- 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!