Crab and tarragon tart

This tart is light, but—at the same time—indulgent.

Roll out the pastry on a lightly floured surface to about 1/8- inch thickness, then use it to line a tart pan with a removable bottom that is 9–10 inches in diameter and 1½– 1¾ inches deep. Leave a little excess pastry hanging over the sides. Let rest in the refrigerator for at least 30 minutes.
Preheat the oven to 400°F. Line the pastry shell with foil and fill with pie weights. Bake until set and lightly golden, 15–20 minutes. Remove the foil and weights and return to the oven to bake until golden brown, about 5 minutes longer. Take the pastry shell out of the oven and let cool slightly. Using a sharp knife, trim off the excess pastry level with the rim.
Reduce the oven temperature to 350°F. Pick over the crabmeat and discard any pieces of shell or cartilage. In a large mixing bowl, lightly beat together the crème fraîche, sour cream, mustard, Parmesan, and lemon zest and juice. Stir in the crabmeat and tarragon, then season well with salt and pepper to taste. Lightly beat the eggs and stir into the mixture. Pour into the pastry shell.
Bake the tart until the filling is puffed and golden on top but still slightly wobbly in the center, 35–40 minutes. Remove the tart from the oven and let it cool a little before slicing and serving.