Prepare Sauce: Combine milk, 1 tsp cocoa powder, and 1 tbsp chocolate spread in a small saucepan. Cook over low heat, stirring constantly until combined. Remove from heat, stir in the butter, and let cool.

Mash & Mix in Pan: Place peeled bananas, eggs, and 3 tbsp chocolate spread directly into a cold, non-stick frying pan. Mash the bananas thoroughly and whisk the three ingredients together until combined.

Complete the Batter: Add the milk, oil, flour, cocoa powder, baking powder, and vanilla to the pan. Whisk until the batter is smooth and free of large lumps. Scrape down the sides of the pan.

Stovetop "Bake": Cover the pan with a tight-fitting lid. Place on the smallest burner at the absolute lowest heat setting.

Cook: Let the cake cook undisturbed for approximately 40 minutes, or until the top is set and a toothpick comes out clean.

Glaze: Allow the cake to cool slightly in the pan. Pour the prepared chocolate sauce over the top, letting it soak in.

Serve: Slice directly in the pan and serve warm.