If you don’t have a Linzer cookie maker, use a scalloped edge 1-1/2″ round cookie cutter and mini heart or shape to cut out center of one cookie. These are sandwich cookies filled with jam. I used strawberry.
½ cup butter, softened
1/3cup sugar
1/3cup confectioner’s sugar
1 egg yolk
1 teaspoon lemon extract
¼ cup heavy whipping cream
1½ cups all-purpose flour
¼ teaspoon salt
Garnish:
½ cup strawberry jam
Sparkling coarse sugar
Find it online: https://lizbushong.com/strawberry-linzer-cookies/