Preheat your oven to 350°F (175°C). Grease an 8x8-inch baking pan or line it with parchment paper for easy removal.
In a large mixing bowl, combine the flour, sugar, cocoa powder, baking powder, and salt. Whisk until well mixed.
In another bowl, mix the melted butter, eggs, and vanilla extract until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Gently fold in the chopped strawberries and chocolate chips, if using.
Pour the brownie batter into the prepared baking pan, spreading it evenly.
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Allow the brownies to cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely.