In a large bowl, whisk together flour, sugar, and salt. Using a pastry blender or your fingers, cut in butter until the mixture resembles fine crumbs. Stir in eggs. Sprinkle 1 Tbsp of the milk over part of the flour mixture; toss with a fork. Push moistened pastry to side of bowl. Repeat moistening flour mixture, gradually adding milk until mixture begins to come together. You may not need to use all the milk.
Gather pastry into a ball, kneading gently just until it holds together. Divide dough into fourths and form four balls. Cover with plastic wrap until dough is easy to handle (up to 1 hour)
Pre-heat oven to 375 degrees and line two large baking sheets with parchment paper. On a lightly floured surface, roll each pastry ball into a 9x8-inch rectangle and then cut the rectangle into four 4 ½x4-inch rectangles.
Brush edges of dough with additional milk. Spoon 1 well-rounded Tbsp of strawberry jam onto half of each rectangle and then fold the other half over the filling. Seal edges with a fork and prick tops. Place on baking sheet and brush with additional milk.
Bake 20-25 minutes, until tarts are turning golden. Remove and cool on metal racks.