Gather your muffin tin and put liners in the tin. Preheat oven to 375 degrees F.
In a Bosch Mixer, add the softened butter and both sugars and cream together.
Add eggs and chia seed/water combo to mixer and mix until combined. Pause if needed and scrape down sides, then mix again just until combined.
Add mashed bananas, sour cream, and vanilla to batter until combined. You don't want to over mix muffin batter, so only mix until combined.
Add flour, salt, baking soda, baking powder, and xanthan gum to batter and mix until just combined-don't over mix! Over mixing causes air pockets to form in the batter, and we don't want that.:)
Your batter should not be thin, this muffin batter is a nice thick batter.
Using a large cookie scoop(small scoop for mini-muffins), scoop one scoop into each prepared muffin tin. Sprinkle just a little granulated sugar on top of each scoop(don’t forget to do this step! It is critical to getting the browning you need). Then bake in a preheated oven for 19-20 minutes or until lightly browned(about 13-14 minutes for mini-muffins)
Remove muffins from tin when baked, and let cool on a wire rack.
Enjoy those delicious, light, and heavenly muffins.