Meanwhile, in a medium saucepan, whisk together the 2 whole eggs, the lemon zest, lemon juice, orange juice, the remaining 7 egg yolks, the remaining 1 cup granulated sugar, and the remaining 1/8 teaspoon sea salt. Cook and stir over medium heat until mixture just thickens, about 10 minutes. Remove from heat. Pour the warm lemon curd through a fine sieve into a bowl; discard solids. Whisk in the 1/4 cup cubed butter, a few cubes at a time, until melted. Whisk in cream. Pour over crust. Bake until just set with a jiggle toward the center, about 25 minutes. Remove to a wire rack to cool completely. Chill at least 2 hours. Lightly sift with powdered sugar, then cut into squares. Store leftovers in an airtight container in the refrigerator for up to 3 days.