Prep your pan and oven. Heat the oven to 350°F (175°C). Line an 8-inch square pan with parchment, leaving overhang for easy lifting. Lightly grease the parchment.

Maccerate the strawberries. In a small bowl, toss the diced strawberries with 1–2 tablespoons of granulated sugar and a squeeze of lemon. Let sit 10 minutes to release juices.

Make a quick strawberry swirl. In another small bowl, stir 1/3 cup strawberry jam with 1–2 tablespoons of the macerated strawberry juices until glossy. Set aside.

Mix the wet ingredients. In a medium bowl, whisk 1/2 cup melted unsalted butter with 3/4 cup granulated sugar until slightly thick. Whisk in 2 large eggs, one at a time, then 2 teaspoons vanilla and 1/4 teaspoon almond extract (if using).

Combine the dry ingredients. In a separate bowl, whisk 1 cup all-purpose flour, 1/2 teaspoon baking powder, and 1/2 teaspoon fine sea salt.

Bring the batter together. Add the dry mixture to the wet and fold until just combined. The batter will be thick and glossy. Gently fold in half of the macerated strawberries (drained) for even distribution.

Assemble in the pan. Spread the batter into the prepared pan. Spoon the remaining strawberries on top. Dollop the strawberry jam mixture across the surface and use a knife to swirl gently. Do not overmix the swirl.

Bake. Bake 22–28 minutes, rotating once, until the edges are set and the center looks slightly soft but not wet. A toothpick should come out with moist crumbs, not raw batter.

Cool completely. Let the pan cool on a rack for at least 1 hour. Lift out using the parchment and cool another 15 minutes before slicing. This step helps the brownies set and turn fudgy.

Optional glaze. Whisk 3/4 cup powdered sugar with 1–2 tablespoons lemon juice (or milk) until smooth. Drizzle over cooled brownies for a sweet-tart finish.