The candied lemon slices and the pistachio crust make this an outstanding tart.
Preheat oven to 375 degrees. Beats eggs in a medium bowl. Whisk in sugar; slowly whisk in cream, lemon juice, zest, and salt.
Place crust on a rimmed baking sheet; pour in egg mixture. Bake until filling is just set, 15 to 20 minutes. Transfer to a wire rack to cool, then chill until firm, at least 2 hours or overnight.
Carefully remove lemon slices from syrup; arrange whole slices over filling (pick best-looking ones to place on top). Cut tart into slices just before serving.