Preheat oven to 350°F (175°C). Lightly grease a 9×5-inch loaf pan and set it aside.
In a medium bowl, whisk together 2 cups Bob’s Red Mill gluten free flour, 1 teaspoon baking powder, 1 teaspoon baking soda, and 1/4 teaspoon salt. Set the dry mixture aside.
In a large bowl, cream together 1/2 cup softened butter and 1/2 cup sugar until light and fluffy.
Add 2 eggs to the butter-sugar mixture and mix until combined. Stir in 2 tablespoons milk and 1/2 teaspoon vanilla.
Mash 4–5 very ripe bananas until you have about 1 1/2 cups mashed banana; stir the mashed banana into the wet mixture until evenly incorporated.
Add the dry ingredients to the wet mixture and stir gently until just combined. Do not overmix.
Fold in 1/2 cup chocolate chips (or your favorite 1/2 cup mix-in) evenly into the batter.
Pour the batter into the prepared loaf pan and smooth the top.
Bake in the preheated oven for 50 to 55 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
Let the bread cool in the pan for at least 15 minutes. Run a knife around the edges if needed, then turn the loaf out onto a wire rack and cool an additional 30 minutes before slicing and serving.