Preheat your oven to 175°C (350°F). Lightly grease your 9-inch square pan or line it with parchment paper for easy removal.
In a mixing bowl, combine 1 cup of all-purpose flour, 1/4 cup of sugar, and a pinch of salt. Add the cold, cubed butter and use a pastry cutter or your fingers to cut it in until the mixture resembles coarse crumbs.
Press this crumb mixture evenly into the bottom of your prepared pan. Use the back of a spoon or your fingers to smooth it out, then bake for about 20 minutes until the crust is just golden around the edges.
While the crust bakes, whisk together the eggs, 1 1/2 cups sugar, 1/4 cup flour, lemon juice, and lemon zest in a bowl until the mixture is smooth and slightly glossy.
Once the crust is baked, carefully pour the lemon filling over it while it's still warm. Return the pan to the oven and bake for an additional 20-25 minutes, until the filling is set around the edges but still slightly jiggly in the center.
Remove the pan from the oven and let the lemon bars cool on a wire rack for about 2 hours. This cooling allows the filling to set completely and develop a smooth, glossy surface.
Once cooled, sift powdered sugar over the top for a snowy finish. Use a sharp knife to cut into neat squares, wiping the blade between cuts for clean edges.
Serve the lemon bars at room temperature or chilled, enjoying the bright, tangy flavor balanced with the buttery crust. Store leftovers in an airtight container in the fridge for up to 3 days.
