Step 1

Preheat your oven to 375°.

Step 2

Cream the butter and sugar for about 5 minutes in a stand mixer. Scrape down the sides as you go.

Step 3

Add in the egg yolks and vanilla, and mix until they are combined.

Step 4

Mix together the flour, cornstarch, and salt. Mix into the creamed butter mixture. Scrape down the bottom and sides as you go!

Step 5

Roll small balls of the dough in your hands and place on a parchment paper-lined baking sheet. Press your thumb into the balls to make an imprint and a little "bowl" for the jam.

Step 6

Microwave some jam for 15-20 seconds. Spoon into the depression made by your thumb.

Step 7

Bake for 9-11 minutes, or until light golden brown around the bottom edge of the cookie.

Step 8

Remove and let cool for 2-3 minutes, and then move to a rack.

Step 9

Let cool 15-20 minutes before icing.

Step 10

To make the icing, whisk together the cream, powdered sugar, and vanilla. Place it into a plastic bag and cut the end off before piping it in a zig-zag pattern.