Preheat the oven to 350°F (175°C). Grease and flour a 9×5-inch loaf pan or line it with parchment paper.

In a medium bowl, whisk together flour, cocoa powder, baking powder, and salt until evenly combined.

In a large mixing bowl, whisk the eggs and sugar until smooth. Stir in the melted butter and vanilla extract until fully combined.

Add the hot fudge sauce to the wet mixture and mix until smooth.

Gradually fold the dry ingredients into the wet ingredients, mixing just until combined. The batter will be thick.

Pour the batter into the prepared loaf pan and spread it evenly.

Bake for 35–45 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs. The top should be slightly cracked.

Allow the bread to cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.

Drizzle extra hot fudge sauce over the cooled bread before serving.