Heat the oven to 350°F. Spray the loaf pan with baking spray or coat with butter. If making muffins, line 8-10 of the pan cavities with paper liner cups.
If using nuts, you can toast them in the oven on a sheet pan for 10 minutes as the oven is preheating.
Melt the butter in the microwave or on the stovetop.
Place the melted butter and sugar into a large bowl and whisk until combined (you can do this in a mixer, too)
Add the eggs. Mix until the mixture is smooth.
Add the milk and vanilla and whisk until until just combined.
Add the mashed bananas and mix until incorporated.
Add the flour, baking soda and salt (I combine these all in a bowl and mix before adding to the batter). Mix until just barely combined. Do not over mix.
Gently fold in nuts or chocolate chips if using.
Pour the batter into the pan. Smooth the top with a spatula. If making muffins, fill each cup about 3/4 full (will make 8-10).
Bake loaf for 50-65 minutes (mine usually takes about 55 minutes). Start checking after 50 minutes. The top should appear caramelized with some of the lighter interior peeking through. A toothpick inserted into the center should come out clean. For muffins, bake for about 20-25 minutes.
Allow loaf to rest about 10 minutes after removing from the oven. Carefully take the loaf out of the pan. Serve slices warm and spread with butter!
