1. Prepare Crust Dough: In a food processor or large bowl, mix the gluten free flour, sugar, and salt. Add the cold, cubed butter and pulse (or cut in with a pastry cutter) until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining.

2. Add Liquid: Mix the apple cider vinegar into the ice water. Drizzle the liquid over the flour mixture, pulsing or stirring gently until the dough just starts to come together. If it’s too dry, add more ice water 1 teaspoon at a time.

3. Chill: Shape the dough into a disk, wrap tightly in plastic wrap, and refrigerate for at least 30 minutes (or up to 2 days).

4. Preheat: Preheat your oven to 375°F (190°C). Grease a standard muffin tin lightly with non-stick spray.

5. Roll & Cut: On a lightly floured surface, roll the dough out to about 1/8-inch thickness. Using a round cookie cutter (approx. 3.5 inches), cut out 12 circles for the bottoms. Use a slightly smaller cutter (or the same one) to cut out 12 circles (or stars/hearts) for the tops.

6. Assemble: Press the larger dough circles into the bottom and slightly up the sides of the muffin cups. Prick the bottoms with a fork.

7. Fill: Place about 1 tablespoon of strawberry jam into the center of each tart. Brush the edges of the bottom crust with a little egg wash.

8. Top: Place the top dough circle over the jam. Press the edges gently to seal (you can use a fork to crimp if they reach high enough, or just press with fingers). Brush the tops with egg wash.

9. Bake: Bake for 20–25 minutes, or until the crust is golden brown and the filling is bubbly.

10. Cool: Allow the tarts to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

11. Glaze: Whisk together the powdered sugar, milk, and vanilla until smooth and spreadable. Spoon over the cooled tarts and immediately top with sprinkles. Let the glaze set before serving.