Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish or line it with parchment paper for easy removal.
In a large mixing bowl, cream together the softened butter and 1 cup of granulated sugar until light and fluffy.
Add 1 1/2 cups of flour and salt, mixing until just combined. Press the mixture into the bottom of the prepared baking dish to form a crust.
Bake the crust in the preheated oven for 15-20 minutes, or until lightly golden.
While the crust is baking, prepare the lemon filling. In another bowl, whisk together the eggs, 1 1/2 cups of granulated sugar, lemon juice, lemon zest, the remaining 1/2 cup of flour, and baking powder until smooth.
Once the crust is done, remove it from the oven and pour the lemon filling over the hot crust.
Return to the oven and bake for an additional 20-25 minutes, or until the filling is set and the edges are lightly golden.
Allow the lemon bars to cool completely in the pan on a wire rack.
Once cooled, dust with powdered sugar, cut into squares, and serve.