Step 1

For the cream cheese swirl: Mix together the cream cheese, sugar and egg white in a small bowl until smooth.

Step 2

For the berries and cream: Gently toss the mixed berries with the sugar, lemon juice and orange zest in a large bowl. Let stand, gently stirring occasionally, until the sugar has dissolved and the mixture is juicy (some of the raspberries will break down), about 1 hour. Refrigerate until ready to serve.

Step 3

For the cake: Preheat the oven to 350 degrees F. Spray a 9-inch square baking dish with nonstick cooking spray and line the bottom with parchment.

Step 4

Whisk together the flour, baking powder and salt in a medium bowl. In a large bowl, beat together the butter and sugar with an electric mixer until light and fluffy. Beat in the vanilla and egg. Add the flour mixture in 3 batches, alternating with the milk and beginning and ending with the flour. Beat until the flour is just incorporated.

Step 5

Spoon the batter into the prepared baking dish and smooth with an offset spatula. Add big dollops of the cream cheese mixture all over the surface and use a small spoon to swirl it in slightly, then smooth the top again.

Step 6

Bake the cake until a wooden toothpick inserted into the center comes out clean, about 30 minutes. Cool the cake in the baking dish for 10 minutes, then remove and cool it completely, cream cheese-side-up.

Step 7

Cut the cake into squares and serve topped with the berries. Add a dollop of whipped cream. Garnish with the mint.