Preheat Oven and Prepare Pan: Preheat your oven to 350°F (177°C). Grease a 9×5-inch loaf pan with nonstick spray and set aside.
Mix Dry Ingredients: In a large bowl, whisk together 1¼ cups all-purpose flour, ½ cup cocoa powder, 1 teaspoon baking soda, and ½ teaspoon salt. Stir in ¾ cup chocolate chips. Set aside.
Cream Butter and Sugar: Using a handheld or stand mixer fitted with a paddle or whisk attachment, beat ½ cup unsalted butter and ¾ cup granulated sugar on high speed until smooth and creamy, about 2 minutes.
Add Eggs and Mix: With the mixer on medium speed, add the 2 large eggs one at a time, beating well after each addition. Then mix in ¼ cup yogurt or sour cream, 1½ cups mashed bananas, and 1 teaspoon vanilla extract until combined.
– Combine Wet and Dry Ingredients: Gradually add the dry ingredients to the wet mixture, beating on low speed. Mix until just combined. The batter will be thick. Avoid over-mixing.
Incorporate Hot Water: Stir in 2 tablespoons hot water to loosen the batter slightly.
– Pour Batter: Pour the batter into the prepared loaf pan and spread it evenly. Sprinkle the remaining 2 tablespoons chocolate chips over the top.
Bake: Bake for 60–65 minutes. To prevent the top from drying out, loosely cover the bread with aluminum foil halfway through baking. Check doneness by inserting a toothpick in the center—it should come out clean with a few small moist crumbs.
Cool: Remove the bread from the oven and let it cool in the pan on a wire rack for at least 1 to 2 hours before removing, slicing, and serving.