01 -
Preheat oven to 350°F (175°C). Line an 8-inch (20 cm) square baking pan with parchment paper, leaving an overhang for easy removal.
02 -
In a medium bowl, whisk together flour, baking powder, and salt. Set aside.
03 -
In a large bowl, whisk melted butter and brown sugar until smooth. Add peanut butter and mix until fully combined.
04 -
Beat in eggs and vanilla extract until well incorporated.
05 -
Gently fold dry ingredients into the wet mixture until just combined—do not overmix.
06 -
Pour batter into prepared pan and smooth the top.
07 -
Dollop raspberry jam over the surface and use a knife or skewer to swirl gently into the batter, creating a marbled effect.
08 -
Bake for 25–28 minutes, or until the center is just set and a toothpick inserted comes out with a few moist crumbs.
09 -
Cool completely in the pan on a wire rack. Lift out using parchment and cut into 16 squares.