Preheat the oven to 350°F (175°C). Line a 9x13 inch baking pan with parchment paper, leaving some overhang for easy removal.

In a mixing bowl, whisk together the melted butter and sugar until smooth. Add the eggs one at a time, mixing well after each addition.

Stir in the vanilla extract.

In another bowl, sift together the flour, cocoa powder, baking powder, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Fold in the semi-sweet, milk chocolate, and white chocolate chips into the brownie batter.

Gently fold in the fresh raspberries, being careful not to crush them.

Pour the brownie batter into the prepared baking pan and spread it evenly.

Bake in the preheated oven for 30 minutes or until a toothpick inserted in the center comes out with a few moist crumbs.

Allow the brownies to cool in the pan for about 15 minutes, then lift them out using the parchment paper and let them cool completely on a wire rack.

Cut into squares and serve.