- 2 eggs
- 1/2 cup sugar
- 1/3 cup freshly squeezed lemon juice (from 3 to 4 lemons)
- 1/2 lemon, zest freshly grated
- 2 tablespoons unsalted butter, slightly softened at room temperature
- 1/2 cup chilled heavy cream
- 1 package puff pastry (2 sheets), thawed
- 2 tablespoons chopped pistachios
- Additional equipment: Flower-shaped or round cookie cutter, preferably fluted, 2 to 2 1/2 inches across, round cookie cutter, 1 inch across, cookie sheet
In the bowl of a mixer, fitted with a whisk attachment (or using a hand mixer), whip the eggs and sugar together until very light yellow and fluffy. Mix in the lemon juice and lemon zest. Rest the mixing bowl in the saucepan, with the bowl's base resting above, not in, the simmering water (pour out some water if necessary). Cook, whisking occasionally, until the mixture is thickened and custard-like, about 10 minutes.
Meanwhile, half-fill a large bowl with ice and cover with cold water. Remove the bowl with the custard in it from the hot water and whisk in the butter until melted. Rest the bottom of the bowl in the ice bath and let cool, folding the mixture occasionally to cool and thicken it.
In a mixer, fitted with a whisk attachment (or using a hand mixer), whip the cream until stiff. Fold into the cooled lemon custard. Cover and refrigerate until ready to serve. (The recipe can be made up to this point and kept refrigerated up to 3 days in advance.)
Heat the oven to 350 degrees F.
Flour a work surface and lay out the puff pastry. Roll the sheets lightly with a rolling pin until smooth and flattened. Use your large cookie cutter to cut out rounds from the puff pastry. Hollow out the centers by pushing halfway down with your small cookie cutter. Do not pull out the centers yet; you'll do that after they are baked. Arrange on an un-greased cookie sheet and bake until golden brown, 15 to 20 minutes. After 10 minutes, rotate the pan to ensure even cooking. When baked, immediately remove to a wire rack and let cool to room temperature.
Cut around the centers with a paring knife to loosen, but don't cut all the way through to the bottom. You want to leave a thin layer of pastry to hold the filling. Pull out the centers to make a hollow in the center of each pastry round.