Using an electric mixer, cream butter, brown sugar, blueberry preserves, vanilla, egg, and egg yolk
In a separate bowl, whisk flour, baking soda, and salt.
Slowly add dry ingredients to the wet ingredients while mixing.
Add White Chocolate Chips
Place cookie dough in a bowl and cover. Chill in the fridge for at least 1 hour.
Preheat oven to 350 degrees.
Line the baking sheet with parchment paper and place 1 inch balls of dough evenly on the baking sheet.
Cook for 10-12 minutes
Remove from oven. Let cool and serve.