📋 Instructions

1. 1Make the pastry dough — Whisk the flour and salt, then cut in the cold butter with your fingertips or a pastry blender until the pieces are the size of peas. Sprinkle in the ice water a tablespoon at a time, tossing with a fork, until the dough just holds when squeezed.
2. 2Chill the dough — Flatten the dough into two discs, wrap them, and refrigerate for at least 30 minutes at 40F (4C). Cold dough rolls without sticking and bakes flakier.
3. 3Cook the hot fudge — Warm the cream in a small saucepan over medium heat until it just steams, about 2 minutes at 200F (93C); small bubbles should ring the edge but it should not boil. Pull it off the heat, add the chocolate chips and let them sit for 1 minute, then stir in the butter and a pinch of salt until glossy and thick enough to coat a spoon.
4. 4Roll and cut — Roll each dough disc on a floured surface to about 1/8 inch (3mm) thick. Cut into 12 rectangles about 3 by 4 inches, re-rolling scraps once.
5. 5Fill and seal — Spoon 2 level tablespoons of cooled fudge onto 6 rectangles, leaving a 1/2-inch border. Brush the border with egg wash, top with a second rectangle, and crimp the edges with a fork.
6. 6Chill before baking — Place the tarts on a parchment-lined sheet and freeze for 10 minutes while the oven heats. Poke three small vents in each top with a toothpick.
7. 7Bake until golden — Bake at 375F (190C) for 22 to 25 minutes, until the edges are golden brown and the tops look dry and set. The filling should be bubbling at the vents; let them cool on the pan for 10 minutes.
8. 8Glaze and finish — Whisk the powdered sugar with milk until pourable, spread over the barely warm tarts, and scatter on sprinkles while the glaze is wet. Top each with a cherry just before serving.