01 - Preheat oven to 350°F. Grease and line an 8x8-inch baking pan with parchment paper.
02 - In a large mixing bowl, blend melted butter, granulated sugar, and strawberry puree with a whisk until evenly combined.
03 - Add eggs and vanilla extract to the mixture and whisk until the batter is smooth.
04 - In a separate bowl, whisk together flour, baking powder, and salt.
05 - Fold dry ingredients into wet mixture until just combined, avoiding over-mixing.
06 - Pour batter into the prepared baking pan and smooth the surface with a spatula.
07 - Place pan in the oven and bake for 22 to 25 minutes, or until edges are set and a toothpick inserted in the center yields a few moist crumbs.
08 - Allow brownies to cool completely in the baking pan.
09 - Whisk powdered sugar, 2 to 3 tablespoons strawberry puree, and lemon juice (if using) until glaze is smooth and pourable.
10 - Spread glaze over cooled brownies. Let set for 15 minutes, slice into squares, and serve.