Instructions:
- Gently warm 1/4 cup of the sugar plum jam in a small saucepan until slightly looser. Set aside to cool slightly.
- In a large bowl, beat the chilled butter, granulated sugar, and salt on medium speed until light and fluffy (about 3 minutes).
- Beat in the vanilla extract and the cooled, warmed jam until just combined.
- Gradually mix in the flour (and cardamom, if using) on low speed until the dough just comes together. Do not overmix.
- Divide the dough in half, flatten each into a disc, wrap tightly in plastic wrap, and chill for a minimum of 60 minutes.
- Preheat oven to 350°F (175°C). On a lightly floured surface, roll one disc of dough to about 1/4-inch thickness. Use a 2-inch cookie cutter to cut shapes. Repeat with the second disc.
- Place shapes on parchment-lined baking sheets. Bake for 12–15 minutes until the edges are just beginning to turn pale gold. Cool completely on a wire rack.
- While cookies cool, prepare the glaze: whisk together the powdered sugar, lemon juice, and the remaining reserved jam until smooth. Adjust liquid for a drizzly consistency.
- Once cool, spread the remaining jam onto the bases of half the cookies. Top with the remaining cookie halves (if making sandwich cookies). Drizzle or dip the tops into the glaze. Let the glaze set completely before storing.