Preheat your oven to 350°F (175°C) and line a baking sheet with parchment.

In a large bowl, whisk together the flour, powdered sugar, and salt until evenly combined.

Add the solid coconut oil in chunks. Use a pastry cutter, two knives, or your fingertips to work it into the flour until the mixture looks crumbly with pea-sized pieces.

Sprinkle the cold water over the crumbs and stir with a fork until the dough just comes together. Add a tiny splash more water only if needed — the dough should be cohesive but not sticky.

Lightly flour a work surface and roll the dough to about 1/8-inch thickness.

Cut the rolled dough into rectangles roughly 4 x 6 inches. Re-roll scraps once or twice if necessary.

Spoon about 1 teaspoon to 1 tablespoon of strawberry jam into the center of each rectangle, leaving a border around the edges.

Fold each rectangle over into an envelope shape and press the edges to seal. Use the heart-shaped cookie cutter to stamp the seam shut or press the edge with a fork to crimp.

Arrange the pastries on the prepared baking sheet, leaving a little space between them.

Bake for 20–25 minutes, or until the edges are lightly golden.

Remove from the oven and allow pastries to cool on the pan for 10 minutes, then transfer to a rack to cool completely before serving.