01 -
Preheat oven to 350°F (175°C). Lightly grease or line an 11x7-inch baking dish with parchment paper, leaving 2-inch overhangs on both sides.
02 -
Combine flour, powdered sugar, salt, and butter in a food processor. Pulse until mixture resembles fine crumbs. Press mixture evenly into the prepared pan and bake for 18 to 20 minutes, or until golden brown.
03 -
Whisk together sugar and flour in a bowl. Add eggs one at a time, whisking well after each addition. Stir in lime zest, lime juice, and food coloring (if using) until smooth and well combined.
04 -
Pour filling over the hot crust and return to the oven. Bake for an additional 18 to 20 minutes or until the filling is set and no longer jiggles.
05 -
Let bars cool completely in the pan for about 1 hour. Then refrigerate for 1 to 2 hours before serving. Lift bars out of the pan using the parchment paper for easy cutting and serving. Store leftovers in the refrigerator.