In a small saucepan over medium heat, combine the raspberries, half a cup of sugar, and just enough water to help dissolve the sugar. Stir gently until the mixture starts to bubble and thicken slightly, about 5–7 minutes.

In another saucepan (or using a microwave-safe bowl), melt the butter along with the semi-sweet chocolate chips until smooth.

In a large mixing bowl, whisk together three eggs and one cup of granulated sugar until well combined. Then add in the melted chocolate mixture and one teaspoon of vanilla extract.

Sift together half a cup of all-purpose flour, half a teaspoon of salt, one-eighth teaspoon baking soda, and one-eighth teaspoon baking powder directly into the wet mixture. Gently fold until just combined.

Pour half of your brownie batter into a greased baking pan (9x9 inches). Spread half of your raspberry sauce over this layer before adding the remaining brownie batter on top. Dollop more raspberry sauce on top and swirl it through gently.

Preheat your oven to 350°F (175°C) and bake for about 30 minutes or until a toothpick inserted into the center comes out mostly clean.