Preheat oven to 355F and line a large baking pan with parchment paper
In a large bowl using a hand mixer or stand mixer, cream together the room temperature butter and powdered sugar. Once smooth add in the egg yolk and mix for another minute.
Add in the vanilla, flour, and corn starch. Mix until the mixture is crumbly like sand. From there use your hands to bring the mixture together.
Roll dough into golf ball shaped balls and place them on the baking sheet. Leave about 1 inch between each cookie. Lightly press down on the cookies to slightly flatted and then press your thumb into the centre to create an indent.
Spoon a teaspoon of jam into the thumbprint indent.
Place cookies into the oven and bake for 13-15 minutes. Once done cooking, remove from oven and allow the cookies to cool for ten minutes on the baking sheet. Remove and let them fully cool on a cooling rack and then enjoy!
Enjoy!
Weekly recipes sent right to your inbox
Want more recipes like this? Sign up for our newsletter