How to Make It
Make tart shell: Whisk flour, sugar and salt in a large bowl. Add butter and vanilla. Stir with a fork just until a soft dough forms. Transfer to a 9-inch tart pan. Press pastry onto bottom and up sides of pan. Chill for 30 minutes.
Arrange rack in lower third of oven and preheat oven to 375°F. Line tart shell with parchment, fill with pie weights. Bake until sides start to turn golden, about 20 minutes. Remove pan from oven; remove parchment and pie weights. Prick shell all over with a fork and bake until golden brown, 10 to 12 minutes. Brush with heavy cream to seal any cracks. Let cool.
Make filling: In a large bowl, whisk together eggs, sugar, orange and lemon juices, cream, and orange and lemon zests.
Set pan on a large, foil-lined rimmed baking sheet. Carefully pour filling into shell and bake until set, 25 to 30 minutes (do not let filling turn brown). Let cool to room temperature, or refrigerate to serve later. Dust with confectioners' sugar just before serving. Serve topped with raspberries and orange zest, if desired.