Preheat and Prepare Pan: Start by preheating your oven to 350°F (175°C). Lightly grease or spray an 8×8-inch (20×20 cm) baking pan to ensure the cake doesn’t stick.

Beat Butter and Sugar: Using an electric mixer, beat 1/3 cup (75 g) of room temperature butter with 3/4 cup (150 g) granulated white sugar until the mixture is light and fluffy, about 2 minutes.

Add Egg: Mix in 1 large egg thoroughly to the butter and sugar.

Incorporate Banana and Milk: Stir in 1 cup (about 235 g) mashed very ripe banana and 1/2 cup (120 ml) milk until fully combined.

Mix Dry Ingredients: In a separate bowl, whisk together 1 1/2 cups (190 g) all-purpose flour, 3/4 teaspoon baking powder, 3/4 teaspoon baking soda, and 1/4 teaspoon salt.

Combine Wet and Dry Ingredients: Add the dry ingredients to the wet mixture and stir just until combined; overmixing can cause the cake to become dense.

Add Chocolate Chips: Fold in 1/2 cup (about 65 g) miniature chocolate chips gently.

Prepare for Baking: Pour the batter into the greased pan and smooth the surface evenly. Sprinkle the remaining 1/4 cup (about 65 g) miniature chocolate chips over the top for extra chocolatey indulgence.

Bake: Place the pan in the oven and bake for 30 to 35 minutes. Check doneness by inserting a toothpick into the center; it should come out clean or with a few moist crumbs.

Cool and Serve: Remove the cake and allow it to cool completely in the pan before cutting. This helps maintain its moist and tender texture.