Preheat your oven to 350°F (175°C) and prepare an 11x7-inch baking dish by greasing it with butter or lining it with parchment paper.

In a food processor, combine flour, powdered sugar, salt, and butter. Pulse until it resembles fine crumbs. Press into the prepared dish and bake for 18-20 minutes until golden and firm.

Whisk together granulated sugar and flour in a mixing bowl. Gradually add eggs, whisking after each addition. Stir in lime zest and fresh lime juice until blended.

Pour the lime filling over the hot crust and smooth the surface with a spatula. Bake for an additional 18-20 minutes until the filling is set and firm.

Let cool in the dish for 1 hour, then refrigerate for 1-2 hours to finish setting.

Lift the bars out using the parchment overhang, transfer to a cutting board, and slice into squares. Dust with powdered sugar before serving.