Save time by using frozen tart shells in this simple recipe for butter tarts. No mixing, chilling, or rolling — just mix up the filling and bake.
Preheat the oven to 400 degrees F (200 degrees C). Place tart shells on a baking sheet.
Whisk brown sugar, melted butter, and vanilla together in a bowl. Whisk in egg until smooth, then stir in half-and-half. Spoon mixture into tart shells, filling each 2/3 full.
Bake in the preheated oven until filling is bubbly and pastry is golden, about 15 minutes.