Preheat oven to 425°F. Line your cupcake tins with liners. I used one jumbo muffin tin (6-count) and (1) 6-count muffin tin with 4 spaces used. This recipe makes 8 jumbo muffins or 15 standard sized muffins.
Add bananas to a large mixing bowl and mash them with a potato masher until thick, and mostly lump-free.
Whisk flour, salt, baking powder, and soda together and set aside.
Add eggs, milk, melted butter, extract, and brown sugar to the mashed bananas. Combine with a spoon.
Slowly add the dry ingredients to the wet ingredients bowl. Combine thoroughly until batter is mixed and streak-free.
Using an ice cream scooper fill muffin tins with batter. If you're making jumbo muffins, fill batter to the top of the liner. If you're making standard sized muffins fill batter 3/4 of the way.
Sprinkle muffins evenly with nuts.
Bake on the center oven rack for 5 minutes at 425°F. Then, reduce the heat to 400°F. and bake for an additional 15-18 minutes. Our muffins were done around the 17-minute mark, but this will vary since the size of your bananas could be larger or slightly smaller. These will have high tops, and will be a deep golden-brown coloring. When you touch the top they should be firm, and not wet. A toothpick inserted inside should come out clean when muffins are done baking.
Allow muffins to cool before removing them from the pan.