In a large bowl, beat the softened butter and granulated sugar together until the mixture is light and fluffy. This usually takes about 2 to 3 minutes.

Stir in the almond or vanilla extract until well combined.

Gradually add the all purpose flour to the butter mixture. Mix on low speed until a soft dough forms. Do not overmix or the cookies will be tough.

Wrap the dough in plastic wrap and let it rest in the refrigerator for about 30 minutes. This makes it easier to handle.

Scoop about 1 tablespoon of dough and roll it into a smooth ball. Place them on a baking sheet lined with parchment paper.

Instead of one round thumbprint, use your thumb or index finger to press two diagonal indents into the center of each ball. This forms a perfect heart shape.

Carefully spoon a small amount of jam into each heart indent. Try not to overfill or it might bubble over.

Bake at 350 degrees Fahrenheit for 12 to 15 minutes or until the edges are just barely golden.

Let the cookies cool on the baking sheet for 5 minutes before moving them to a wire rack.