Preheat the oven to 350 degrees.

For the crust, cream the butter and sugar until light in the bowl of an electric mixer fitted with the paddle attachment. Combine the flour and salt and, with the mixer on low, add to the butter until just mixed. Dump the dough onto a well-floured board and gather into a ball. Wrap the ball in saran wrap and chill in the fridge for at least 30 minutes.

After dough has chilled, take pieces of the dough and push it into the bottom and up the sides of well greased mini mason jars.

Bake the crust inside the jars for 15 to 20 minutes, until very lightly browned. Leave the oven on and let them cool on the counter.

While they are cooling, make the filling. Whisk together the eggs, sugar, lemon zest, lemon juice, and flour. Pour over the crusts (don't fill the jars to the brim!) and bake for 35 minutes or until the filling is set. Each oven is different so watch it carefully. It might take longer. Let cool to room temperature. I prefer my lemon bars cold, so after they cool, I pop them in the fridge with lids on. Another plus, you can keep them in your fridge and eat them nightly all week for dessert! So yum and so terrible with bikini season on the horizon, but they are that delish!