Shortbread Thumbprint Cookies

Preheat oven to 300 degrees (F).

Mix butter, sugar, and vanilla together. (The Argo recipe says to use an electric mixer for this. I just mix it well with a spoon.)

In another bowl, use a whisk to blend flour and cornstarch together. Gradually add dry ingedients to wet ingredients, mixing well after each addition. (I begin mixing this with a spoon but eventually it is easier to mix and blend together by hand kneading it.)

Roll into 1-inch balls. Press thumb down into each ball to form a deep little bowl. Place on parchment lined baking sheet. (I do this in case I spill jam onto the baking sheet.)

Put a little glop of jam (or jelly) into each cookie bowl. Try to only half fill each little bowl.

Bake for 25-30 minutes.

Makes about 4 dozen cookies.