Heat the oven to 350°F (175°C). Line an 8-inch square baking pan with parchment paper, leaving enough overhang on two sides to lift out the cooled blondies.

Whisk the melted, slightly cooled butter and granulated sugar together until smooth. Add the eggs, vanilla, lemon zest, and lemon juice, then whisk until the mixture is evenly combined.

In a separate bowl, stir together the flour, baking powder, and fine salt. Add the dry mixture to the butter mixture and fold just until no dry streaks remain.

Gently fold in the finely diced strawberries. Spread the thick batter evenly in the prepared pan, taking care not to crush the fruit.

Bake for 28–35 minutes, until the edges are lightly golden and the center is set. A toothpick inserted in the middle should come out with a few moist crumbs but no wet batter.

Cool the blondies completely in the pan for 30–45 minutes before glazing. For especially clean slices, chill the cooled blondies briefly after they reach room temperature.

Stir the confectioners’ sugar with 1 1/2–2 tablespoons fresh lemon juice, adding enough juice to create a thick but pourable glaze. Drizzle it over the cooled blondies, sprinkle with optional lemon zest, and let it set before cutting.