Preheat the oven to 350F, rack in the middle. Line 2 baking sheets with parchment paper. In a large mixing bowl combine the flour, baking powder, and salt. Add the shortening and cut it into the flour mixture with a pastry cutter. Add the milk all at once and mix it in with a spatula until it begins to come together.
Lightly flour your hands and the countertop and turn the dough out onto the countertop. Gently work the dough to form a ball. Divide in half and wrap each ball in plastic and chill for 1 hour. Remove one ball from the fridge leaving the other to chill.
On a very lightly floured surface, roll the dough into a 12×10” rectangle. Cut into 8 5×3” rectangles. Place 4 rectangles about 1” apart on a baking sheet. Spoon 1-2 tablespoon of strawberry preserves over 4 of the rectangles spreading until it’s about 3/4” from the edges. Lightly brush the edges of the dough that does not the filling on it with the egg wash. Top each with a dough rectangle. Gently press the edges to seal then using the tines of a fork to double seal. Repeat with the other dough ball to make 2 full trays.
Lightly brush with the egg wash mixture over the edges again. Using a toothpick, poke 4-6 holes in the top of the dough to allow for air to escape. Bake for 25 to 30 minutes or until golden brown. Move to a rack and allow to cool.
Make the Glaze
Place the gelatin in hot water and mix until granules are dissolved. Mix gelatin mixture with confectioners’ sugar until smooth. Spread the icing on top and decorate with sprinkles. Allow to cool completely. Store in a covered container
Notes
*If you want vegetarian version you need to buy vegetarian unflavored gelatin.