Preheat oven to 350 degrees F and spray a 9-inch non-stick removable bottom tart pan with non-stick spray.

In the bowl of your electric mixer cream the butter and sugar until light and fluffy.

Add the flour and salt and beat until the dough just comes together.

When making this crust the dough will first look very crumbly but just keep mixing until you see it come together in the bowl. This takes around 3 minutes.

Press crust into the bottom of your greased pan and bake for about 20 minutes, or until lightly browned.

Remove from oven and place on a wire rack to cool while you make the filling.

In a bowl of a food processor add lemon slices, sugar, and butter.

Process together until completely smooth. Scraping down the sides when needed.

Add in eggs, cornstarch, and kosher salt and process until combined and smooth.

Carefully pour the lemon mixture into the crust. Be careful to not fill the crust over the top or it will not remove correctly.

Add tart to a baking sheet and bake for about 35 minutes until the filling is set and the center of the tart is just slightly jiggly. The top should also be a light golden color.

Let the tart completely cool before popping it out of the tart mold.

Serve room temperature lightly sprinkled with powdered sugar.