These pastry cups make it easy to impress a crowd and highlight the perfect combination of tart lemon juice and subtle blueberries. For a shortcut, use store-bought puff pastry to make the cups.
Preheat the oven to 400 degrees.
In a food processor fitted with the metal chopping blade, combine the flour and salt and pulse to combine. Add the butter and cream cheese and pulse about 10 times, until the mixture begins to clump together. Gather up the dough and shape it into a thick disk. Wrap the dough in plastic wrap and refrigerate it until it is chilled and easy to handle, about 2 hours.
Position the rack in the center of the oven. Butter two 12-cup miniature muffin pans. Divide the dough into 24 balls. One at a time, place a ball of dough in each muffin cup and use your fingers to press it firmly and evenly up the sides to make a pastry shell. (A wooden tart tamper, available at kitchenware shops and online, can help the job go quickly.) Pierce the shells with a fork. Freeze for 5 minutes.
Bake until the shells are golden brown, about 10-12 minutes. Let the shells cool in the pans for 5 minutes. Carefully remove from the pans and cool completely.
The pastry shells can be stored in a covered container for up to 1 day.
Put a wire sieve in a bowl and place it near the stove. In a medium-sized bowl, whisk the egg yolks, sugar, and lemon juice together. Pour this mixture into a heavy, medium-sized saucepan and add the butter.
On medium heat, cook the mixture for about 10 minutes, whisking constantly, until it is thick and steaming.Immediately strain the curd through the sieve to remove any bits of cooked egg white. Stir the lemon zest into the curd. Press a piece of plastic wrap directly onto the surface of the curd and let it cool. Transfer the curd to a covered container. Refrigerate the curd until it is chilled and spreadable, at least 2 hours.
The curd can be stored in the refrigerator for up to 5 days.
To serve, spoon the lemon curd into the pastry cups. Top each with three blueberries and a bit of candied lemon zest and serve immediately.