In a glass measuring cup, whisk together buttermilk, eggs, and vanilla. Slowly whisk the butter into the egg mixture.
Add liquid ingredients to the dry ingredients and combine using a rubber scraper or wooden spoon with a few swift strokes. It's ok if there are lumps.
Pour ½ cup batter per pancake onto the hot griddle. Sprinkle with bananas, walnuts, and chocolate chips, pressing lightly to adhere. Cook several minutes, until edges begin to dry and bottom is golden brown. Flip and cook a few minutes more.
The pancakes are delicious on their own, or serve with butter and maple syrup, if desired.
Tips for customizing
Swap the bananas for another fruit like thinly sliced ripe peaches or nectarines, raspberries, or blueberries
Skip the walnuts or swap them with pecans
Use carob chips or cacao nibs instead of chocolate chips
Use all-purpose flour for all of the flour instead of making some of it whole wheat
Drizzle cooked pancakes with your favorite nut butter for even more protein