Prep: Preheat oven to 350°F (180°C / 160°C fan convection). Line a 9-inch square baking pan with parchment paper.

Brownie Layer

Wet Ingredients: In a large bowl, beat 3 eggs and 1 ¼ cups granulated sugar with a mixer until pale, thick, and ribbon-like (≈5 minutes).

Chocolate Mix:

Melt 10.5 oz dark chocolate and ¾ cup (1½ sticks) unsalted butter in a microwave-safe bowl in 30-second intervals, stirring until smooth.

Combine: Slowly pour the melted chocolate mixture into the egg-sugar blend while mixing on low. Fold in 1 cup all-purpose flour and ½ tsp salt until just incorporated.

Layer: Reserve ⅓ cup of brownie batter for swirling. Pour the rest into the prepared pan, smoothing the top.

Cheesecake Swirl

Mix Filling: In a separate bowl, blend 13 oz softened cream cheese, 1½ cups powdered sugar, 1 tsp vanilla extract, and 2 eggs until creamy and smooth.

Assemble: Pour cheesecake batter over the brownie layer. Dot with reserved brownie batter, then swirl gently with a knife to create a marbled effect.

Bake & Cool Bake 30–35 minutes until edges are golden and the center slightly jiggles (less time = fudgier; more time = firmer).

Let cool completely in the pan—this ensures clean slices! Chill 2 hours for neater cuts.