Cook raspberries and one tablespoon sugar in a medium saucepan over medium heat until they are soft and release their juices, about 5-7 minutes. Puree in a food processor. Strain through a fine sieve to remove the seeds. Set aside to cool completely.

In the bowl of a stand mixer fitted with a paddle attachment, cream the butter and one cup sugar on medium speed until light and fluffy. Add the egg yolks, one at a time, and vanilla until well blended, scraping down the bowl occasionally. Gradually add the flour mixture and beat until well blended and no longer crumbly. Remove half of the dough from the bowl and form into a small disk. Set aside. To the remainder of the dough in the bowl, add 3 tablespoons of the raspberry puree and the additional 5 tablespoons of flour. Beat until the dough is all the same color. Form dough into a disk.

Roll out each disk of dough between two sheets of wax paper into roughly 14x8 rectangles and 1/8 inch thick. Slide the dough onto two large baking sheets and refrigerate for about 1 hour.

Place nonpareil decors in a 9x13 pan. Set aside.

Remove dough from refrigerator. Lay rectangles side by side with the long side closer to you and carefully peel away top layer of wax paper from both doughs. Brush the top of the raspberry dough very lightly with water. Place vanilla dough on top of raspberry dough paper side up. Roll over the top of the wax paper with your rolling pin very gently to seal the dough together. Carefully remove top sheet of wax paper from the vanilla dough. Trim up the edges of the dough to make a nice neat rectangle.

Beginning with the long side, roll the layers into a nice tight cylinder. As you roll, peel off the bottom sheet of wax paper. Press at the seam to seal and trim the ends. Gently roll the log in the nonpareil decors until completely coated. Wrap tightly in wax paper and refrigerate for 3-4 hours or until firm enough to slice.

Preheat oven to 325 degrees. Slice the log into 1/4 inch slices and place on parchment lined baking sheets, one inch apart. Bake one sheet at a time for 12-14 minutes, or until tops are firm and bottoms are lightly browned. Let cool on baking sheet for 5 minutes then remove to wire racks to cool completely. Can be stored in airtight container at room temperature for up to 4 days.