Combine the two via folding, do not overmix. Your batter should be pourable and spreadable. If it is too dry, add a tbsp water and mix again. If it's too runny like pancake batter, add a tbsp more flour.
Fold in sprinkles. Transfer to loaf pan.
Bake 35-40 minutes (20-25 for muffins) until knife comes out clean. Cool completely.
Spread frosting on, let it set in the fridge.
Slice and enjoy!
Notes
To make a flax egg, stir together 1 tbsp (7 g) flax seed meal and 3 tbsp water and let it sit and thicken for 5 minutes.
If you want to make a homemade mini-batch frosting, whisk together 3 tbsp powder sugar (20 g) with 1 tbsp softened (plant) butter or cream cheese (15 g), add a drop of milk or more powder sugar to bring to the desired consistency. Enjoy!