First, make the crumble topping. In a medium bowl, combine all of the crumble topping ingredients (the flour, quick oats, butter, cinnamon, 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.
Make the muffin batter! It will need to rest at room temp for 20 minutes before baking. First, in a large bowl, using an electric mixer, beat the eggs, white sugar, and brown sugar until lighter (2 minutes). Add the oil, milk, and vanilla and beat to combine then add the flour, starch, almond flour, cinnamon, baking powder, and salt and beat to combine. Finally, fold in the rolled oats and chocolate chips until smooth.
Place your six 4-inch cake pans on a cookie sheet and grease each pan with cooking spray or room temp butter, then spoon batter into each one evenly (they should be about 3/4 full). Then press the crumble topping onto the muffin batter in each pan and press in a few chocolate chips (optional).
Then let the batter sit either on the counter for 20 minutes before baking. Once the batter has rested preheat the oven to 425° Fahrenheit. Bake for 5 minutes and then turn down the temperature to 350° (without opening the oven door!! Keep it closed) and continue 30-40 minutes until a skewer inserted into the center of a muffin comes out clean (do NOT open the oven while baking or the muffins will not rise fully, only open the oven a tiny bit to check if done). Let cool nearly-completely before turning out.