In a large bowl, stir together flour, sugar and salt. With electric mixer, beat in the butter one stick at a time. Beat in cream cheese and vanilla until dough begins to form a ball. Knead dough in the bowl a few times. Divide dough in half; form each half into a flat 4-inch disc. Wrap with plastic and chill in refrigerator for 20 to 30 minutes to make rolling easier.

Roll one disc of dough between 2 sheets of parchment paper to a ⅛-inch thickness. Repeat with remaining dough. Place rolled-out dough sheets with paper in refrigerator for 10 minutes.

Preheat oven to 350°. Remove one sheet of dough from refrigerator. Remove paper; cut out squares with a cookie cutter. Make half of the squares decorative by cutting a smaller shape from the center for jam to show through when assembled.

Arrange squares on ungreased cookie sheets. Repeat with remaining dough. Bake for 10 to 11 minutes or until bottoms are just golden.

Cool cookies 1 minute before transferring to a wire rack to cool completely.

In a small saucepan, simmer jam over medium-low heat, stirring often, about 10 minutes or until slightly thickened and reduced to 1 cup. Cool 10 minutes before filling cookies.

Spoon a small amount of jam onto the full squares, spreading almost to edge. Place a square with a cutout on top. Detailed cutouts may need jam applied to assembled cookie with a tiny spoon or toothpick to fill in small spaces.