Step 1

Preheat oven to 350 degrees. Grease a 9 x 13 baking pan.

Step 2

In a 2 quart heavy saucepan over low heat, melt the butter and chocolate. Use a wire whisk or spoon to beat in 3 eggs and 2 cups of sugar until all of the ingredients are well combined.

Step 3

Use a wooden spoon to stir in the flour, salt and 1 teaspoon of vanilla extract. Pour mixture evenly in the pan and set aside.

Step 4

With electric mixer on low speed, beat the cream cheese, 1/2 cup of sugar, 1 egg and 1 teaspoon of vanilla until just combined. Increase speed to medium and continue to beat for another two minutes. Scrape the bowl occasionally with a rubber spatula. The mixture should have thickened.

Step 5

With a large spoon, drop spoonfuls of the batter on top of the brownie layer. Use the tip of a sharp knife to lightly score the surface in a swirly pattern so the two batters combine slightly.

Step 6

Bake for 40-45 minutes until a toothpick inserted in the middle comes out clean. Cool on rack for 20 minutes and then refrigerate for an hour. Cut into bars. Refrigerate leftovers.