Preheat your oven to 350°F (175°C). Line an 8-inch baking pan with parchment paper and lightly coat with cooking spray.

In a saucepan, combine raspberries, sugar, and water over medium heat. Stir until saucy and thickened, about 8-12 minutes. Strain to remove seeds and cool.

Melt chocolate and butter together in a saucepan over low heat, stirring until smooth. Cool slightly.

In a mixing bowl, whisk together eggs, sugar, and vanilla until frothy. Gradually add cooled chocolate mixture, stirring constantly.

Sift flour, baking powder, baking soda, and salt in a separate bowl. Fold into the wet ingredients until just combined.

Pour batter into the prepared pan. Drop spoonfuls of raspberry sauce across the surface and gently swirl with a knife.

Bake for about 30 minutes or until a toothpick comes out with a few moist crumbs. Do not overbake.

Cool in the pan for at least 2 hours before lifting out and slicing into squares.