In a mixer fitted with the paddle attachment, beat softened butter with powdered sugar until fully combined. Add egg yolk, raspberry jam, and food coloring. Mix until well combined.
Add flour and salt and mix only until dough comes together. Careful to not overmix.
Place dough on piece of parchment paper and roll into a log about 1 1/2 inches in diameter. Freeze dough for approximately 2 hours, or until log is chilled all the way through. You can freeze dough for up until one month.
Preheat oven to 350 degrees. Line baking sheet with parchment.
Remove dough from fridge. Put granulated sugar in a large rimmed baking sheet.
Brush the reserved egg white on the outside of the cookie dough.
Roll in granulated sugar until completely coated. Return to fridge for 5 minutes to chill.
Remove from fridge and slice roll into 1/4 inch slices. Place on parchment lined sheet approximately 1 inch apart.
Bake for 8-10 minutes or until cookies just begin to turn color and the edges are golden brown.
Remove cookies from oven and transfer to a cooling rack. Cool completely and store in an airtight container for up to one week.