1/2 cup (8 Tbsp; 113g) unsalted butter, softened to room temperature
3/4 cup (150g) packed light or dark brown sugar
2 large eggs, at room temperature
1/3 cup (80g) plain yogurt or sour cream, at room temperature
2 cups (460g) mashed bananas (about 4 large ripe bananas)
1 teaspoon pure vanilla extract
Optional: 3/4 cup (100g) chopped pecans or walnuts