Position rack in center of oven and preheat to 350 degrees F. Line a standard 12-hole muffin tin with paper liners or grease with butter; set aside. Spread nuts on parchment lined rimmed baking sheet and bake until fragrant and deep golden brown, about 10 minutes. Transfer nuts to cutting board to cool then chop coarsely and set aside.

In a medium bowl, sift together the flour, baking soda, salt and nutmeg; set aside. In a small bowl, gently mash 2 of the bananas with a fork so they still have some texture; set aside. In the bowl of an electric mixer fitted with a wire whisk, beat remaining 2 bananas and sugars together until well combined and smooth. Add melted butter, milk, egg, and vanilla and beat until completely incorporated, scraping down sides of bowl as needed. Add dry ingredients and mix until just incorporated. Using a spatula, gently fold in toasted nuts and reserved mashed bananas. Divide batter evenly among prepared muffin cups. Rap muffin tin on counter to remove any air bubbles.

Bake until muffins are golden brown and a toothpick inserted into center of a muffin comes out clean, about 25 to 30 minutes. Let cool in muffin tin set on wire rack for a few minutes before turning muffins out. Serve warm or at room temperature.

Makes 12 muffins.

* Bananas should be VERY ripe (i.e., as much black as possible on the skins), but not spoiled. This is a good use for bananas that have gotten too ripe to eat whole. You can freeze bananas before they spoil -- but after they have over-ripened -- and thaw just before making your muffin batter.