In a large microwave-safe bowl, place butter and chocolate. Heat in microwave at 30 second intervals until the chocolate and butter have melted. Stir between each interval.
½ cup butter, 2 ounces unsweetened chocolate
Stir in sugar. Allow the mixture to cool slightly before adding eggs.
1 cup sugar
Stir in eggs and vanilla.
2 eggs, 1 teaspoon vanilla bean paste
Stir in flour. Stir just until the flour is incorporated.
⅔ cup flour
Pour batter into a greased 8x8 inch baking dish.
Cheesecake Layer
In a clean mixing bowl, whip cream cheese with an electric hand mixer until smooth and creamy.
8 ounces cream cheese
Mix in sugar, egg, and vanilla.
¼ cup sugar, 1 egg, ½ teaspoon vanilla bean paste
Pour mixture on top of the brownie layer. Use a knife to create swirls of both layers.
Bake in a preheated 350°F oven for 35-40 minutes until the center is no longer jiggly, and the edges are just slightly puffed.
Notes
Soften the cream cheese fully so the cheesecake layer mixes smoothly and is creamy without lumps.
Do not overmix the brownie batter once the flour is added. Stir just until combined to keep the brownies tender.
Let the brownies cool completely before cutting so the layers set and the slices hold their shape.