In a medium saucepan, combine fresh raspberries, sugar, and water. Cook over medium heat for 5–7 minutes until thickened, then strain to remove seeds.

Preheat your oven to 350°F (175°C) and line an 8x8-inch baking pan with parchment paper.

In a small saucepan over low heat, melt chocolate chips and butter until smooth (about 3–5 minutes).

In a large mixing bowl, whisk together eggs, sugar, and vanilla until frothy, then stir in the cooled chocolate mixture.

Sift together flour, baking powder, baking soda, and salt in a separate bowl. Fold into the chocolate mixture gently.

Pour half of the batter into the baking pan, drizzle half of the raspberry sauce on top, add remaining batter, and swirl in the rest of the sauce.

Bake for 30 minutes, checking for doneness with a toothpick.

Allow to cool in the pan for 30 minutes before lifting out and slicing into squares.