Amazing raspberry-filled and almond-flavored shortbread thumbprint cookies. These jam thumbprint cookies are irresistibly good and perfect for a holiday cookie platter!
In a large bowl, add the room temperature butter and sugar. Beat at medium speed until smooth and creamy, scraping the sides as needed. Add in the almond, vanilla extract, cornstarch, and salt and beat until combined. Add flour into the bowl. Beat together at low speed, scraping bowl as needed, until ingredients are all combined. Do not overmix.
Preheat the oven to 350 degrees F. Bake the cookies for 8-10 minutes or until very lightly browned (slightly underbake for soft and delicious shortbread cookies!)
Remove cookies to a cooling rack and allow them to cool completely. Meanwhile, prepare the glaze by whisking all the ingredients together in a bowl until smooth. (Add heavy whipping cream or milk until you've reached your desired consistency; I like the glaze on the thicker side).
Drizzle the glaze over the cookies and allow to set. Cookies best enjoyed within 3-4 days; store in an airtight container.