Melt 1 cup of unsalted butter in a microwave or saucepan, allowing it to cool slightly for about 5 minutes.

In a large mixing bowl, whisk together the melted butter and 2 cups of granulated sugar until smooth.

Incorporate 1 cup of unsweetened cocoa powder, 1 teaspoon of salt, and 1 teaspoon of baking powder into the butter-sugar blend.

Stir in 1 tablespoon of vanilla extract and then add 4 large eggs, one at a time, mixing after each.

Gradually fold in 1 cup of all-purpose flour until just combined.

Gently fold in 1 cup of semi-sweet chocolate chips.

In a small saucepan, combine ½ cup of heavy cream, ½ cup of semi-sweet chocolate chips, 2 tablespoons of unsalted butter, 1 tablespoon of corn syrup, and ¼ teaspoon of salt. Heat over low for about 5 minutes.

Preheat your oven to 350°F (175°C) and grease and flour a 9x5 inch loaf pan.

Pour half of the brownie batter into the prepared pan and drizzle half of the hot fudge swirl over it.

Pour the remaining brownie batter over the fudge, then drizzle the rest of the hot fudge swirl on top.

Gently swirl the hot fudge into the batter, then bake for 50-60 minutes.

Let the bread cool in the pan for 10-15 minutes before transferring to a wire rack.

Slice and serve warm or at room temperature.

To store, wrap it tightly for up to 3 days at room temperature, or refrigerate for a week.