Step 1

Mash 2 bananas in a large bowl with a fork until smooth (about 1 cup mashed banana). Add 1 cup milk, 1 large egg, and 2 teaspoons vanilla extract, and whisk until combined.

Step 2

Add 1 cup all-purpose flour, 3 tablespoons packed light brown sugar, 2 teaspoons baking powder, 1/2 teaspoon ground cinnamon, 1/4 teaspoon ground nutmeg, and 1/4 teaspoon kosher salt. Stir with a rubber spatula until just incorporated but no dry spots remain. Stir in 1/4 cup chopped walnuts.

Step 3

Heat 2 tablespoons of the unsalted butter in a large cast iron skillet, nonstick frying pan, or griddle on medium heat until melted. Drop 3 (1/4-cup) portions of the batter into the pan and spread out each portion into a 4-inch round. Reduce the heat to medium-low and cook until bubbles start forming on the top and the edges start to brown, 3 to 4 minutes. Flip the pancakes and cook until the bottoms easily release from the pan and are golden brown, 3 to 4 minutes more.

Step 4

Transfer the pancakes to a warm oven or plate. Repeat cooking the remaining batter, wiping out the pan between batches and adding more butter between each batch. Serve immediately with sliced banana, walnuts, and maple syrup.