Preheat the oven to 350F. Grease or line a muffin pan.
In a large bowl, whisk the wet ingredients together: melted butter, maple syrup, mashed bananas, eggs, cinnamon, nutmeg, and vanilla extract.
Add the sifted einkorn flour, baking powder, baking soda, and salt. Stir to combine. Don't over-mix the batter. Just stir until the ingredients are combined.
Scoop the batter into the muffin pan (it will be thick). I use an ice cream scooper.
Bake the muffins for 18-22 minutes, until firm on top. Allow the muffins to cool for a few minutes before enjoying.
For storage, I keep the muffins in an air-tight container in the fridge for up to a week. They also freeze well.
Notes
*I haven't tried making these with whole wheat einkorn flour. I'm sure you can. I recommend reducing the flour by 1/4 cup if using whole wheat flour.