Dulce de Leche Brownies

I'm feeling a bit under the weather but I really want to make use of the dulce de leche I made last night so I didn't dare make my life difficult and try anything fancy. What could be simpler than good old brownies? I thought about dense, fudgy, and moist brownies with the dulce de leche oozing out as I slice them. I've made some with cream cheese swirls, with nuts, salty and sweet, but this is the first time I used this gooey concoction. This is an absolute comfort food which is best served with vanilla ice cream or a glass of cold milk or simply by itself. Here's the recipe:

Dulce de Leche Brownies

Ingredients:
1 stick unsalted butter
1 cup bittersweet or dark chocolate, finely chopped
1/4 cup unsweetened cocoa powder
3 large eggs
1 cup granulated sugar
1 tsp pure vanilla extract
1 cup all-purpose flour
1 cup Dulce de Leche

Directions:
1. Preheat the oven to 350 degrees F.
2. Line a 8-inch (20 cm) square pan with a long sheet of aluminum foil and grease the bottom and sides with non-stick spray
3. Melt the butter in a medium saucepan. Add the chocolate pieces and stir constantly over low heat until the chocolate is melted.
4. Remove from heat and whisk in the cocoa powder until smooth.
5. Add in the eggs one at a time, then stir in the sugar, vanilla, then the flour.
6. Spread half of the batter into the prepared pan. Pour a portion of the dulce de leche on top of the batter, evenly spaced then run a knife through to create a swirl effect
7. Spread the remaining brownie batter on top and smooth gently with a spatula
8. Drop spoonfuls of the remaining dulce de leche on top and run the knife through for the final touch
9. Bake for 30-32 minutes until the center becomes lightly firm. Remove from the oven and cool completely before slicing. It can be served warm with vanilla ice cream as brownie ala mode or with a glass of cold milk.