Preheat your oven to 350°F (175°C).
Lightly grease a 9x5-inch loaf pan and line it with parchment paper for easy removal.
In a large mixing bowl, whisk together the melted butter, vegetable oil, granulated sugar, and brown sugar.
Add the eggs one at a time, beating well after each addition.
Stir in the vanilla extract for extra flavor.
Sift the flour, cocoa powder, baking powder, and salt into a separate bowl.
Gradually add the dry mixture to the wet mixture. Mix until just combined to avoid over-mixing.
Fold in the semi-sweet chocolate chips using a spatula.
Pour half of the batter into the loaf pan, then drizzle with half of the hot fudge sauce. Add the remaining batter and top with more fudge, creating swirls with a knife.
Bake in the preheated oven for 50–55 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Allow the brownie bread to cool in the pan for 10 minutes, then transfer it to a wire rack to finish cooling.