In a medium bowl, combine the flour, baking powder, salt, cinnamon, and confectioners' sugar. Stir until well blended.

In another bowl, beat the softened butter and granulated sugar together until light and fluffy.

Incorporate the vanilla extract and large egg into the butter-sugar mixture and beat until thoroughly combined.

Gently fold the dry mixture into the wet ingredients until just combined.

Divide the dough into two portions, shape into disks, wrap in plastic wrap, and refrigerate for at least 2 hours.

Preheat your oven to 375°F (190°C).

Roll out each disk on a lightly floured surface and use heart-shaped cookie cutters to create shapes.

Chill the cut-out cookies on baking sheets for an additional 5 minutes.

Bake cookies for 8-10 minutes, or until edges are set and lightly golden.

Cool cookies on baking sheets for 2 minutes before transferring to a wire rack.

Warm the strawberry jam in a saucepan.

Spread warm strawberry jam on half of the cookies and top with the remaining cookies.

Dust with confectioners' sugar if desired and serve.