8tablespoons[1 stick or 113 g] unsalted butterat room temperature
FOR THE FILLING
In the bowl of a food processor fitted with a blade, process the freeze-dried raspberries until they reduce to a powder.
In a medium bowl, mix together the cream cheese, processed raspberries, sugar, flour, vanilla, and salt until no lumps remain. Add the egg and mix again until combined. Add the food coloring if using and mix to combine.
FOR THE BROWNIES
Adjust an oven rack to the middle of the oven. Preheat the oven to 350°F [180°C]. Grease a 9 by 13 in [23 by 33 cm] baking pan and line with a parchment sling.
In a small bowl, whisk together the flour, salt, and baking powder.
In a large bowl, whisk together the eggs, granulated and brown sugars, oil, and vanilla.
Place the chocolate and butter in a small, heavy-bottom saucepan set over low heat and melt together, stirring frequently to prevent the chocolate from scorching. Continue cooking until the mixture is smooth.
Add the white chocolate mixture to the sugar-egg mixture and whisk until smooth. Add the flour mixture and stir with a spatula until just combined.
Put two-thirds of the brownie batter in the prepared pan. Dollop the cream cheese and remaining brownie batter over the top, alternating the two. Drag the tip of a butter knife through the batter, creating swirls.
Bake until the sides of the brownies have set, the top is starting to crackle and look glossy, and a wooden skewer or toothpick inserted into the center comes out with crumbs, 28 to 34 minutes. The batter on the toothpick should not be wet but should have a good amount of crumbs clinging to it.
Transfer the pan to a wire rack and let cool completely. Use the parchment sling to gently lift the brownies from the pan. Cut them into bars and serve. Store brownies in an airtight container at room temperature for up to 2 days.
I recommend using a good white chocolate, such as Guittard’s white chocolate baking wafers or Valhrona Blond Dulcey feves.