Press the crust into the tart pan. Press aluminum foil on to top of crust, then put 2-3 cups dried beans on foil (acts as weight to hold foil down). Bake 12 mins at 425 degrees. Remove foil and beans, and bake for additional 3 minutes. Let crust cool.
Mix juice, zest, sugar, eggs, and salt; whisk well. Cook over medium heat, until mixture thickens (approximately 14 minutes), whisking constantly. Remove from heat, and gradually whisk in butter until mixture is smooth. Pour into crust and bake 15 minutes at 300 degrees. Cool before cutting. Serve with berries and whipped cream.