Preheat your oven to 350°F (175°C) and line an 11x7-inch baking dish with parchment paper.

Blend together the all-purpose flour, powdered sugar, and salt in a food processor. Add the cold butter and pulse until it resembles coarse crumbs. Press this mixture into the bottom of the baking dish.

Bake the crust for 18-20 minutes until golden brown around the edges.

In a mixing bowl, whisk together the granulated sugar and flour. Gradually add the eggs, whisking until smooth. Stir in lime zest and juice, and food coloring if desired.

Pour the lime filling over the hot crust and spread evenly. Bake for another 18-20 minutes until the center is set.

Let the Lime Bars cool completely in the pan for about 1 hour, then refrigerate for 1-2 hours before slicing.

Carefully lift the Lime Bars out of the pan and slice into squares. Dust with powdered sugar if desired before serving.