In a small bowl, combine granulated sugar and cinnamon.In the bowl of stand mixer fitted with the paddle attachment, beat butter at medium speed just until creamy. Add ⅓ cup (67 grams) cinnamon sugar, confectioners’ sugar, and salt, and beat until smooth, about 1 minute, stopping to scrape sides of bowl. Add 1 egg yolk (18.5 grams) and vanilla, and beat for 1 minute. With mixer on low speed, add flour, beating just until combined.Turn out dough onto a lightly floured surface. Press and knead until dough comes together. Divide dough in half, and roll each half into a 7-inch log. Wrap logs in plastic wrap, and refrigerate for at least 4 hours or up to 2 days.Preheat oven to 350°F (180°C). Line 2 baking sheets with parchment paper.Using a sharp knife, cut dough into ½-inch-thick rounds. Beat remaining egg yolk (18.5 grams) and brush top of rounds; dip in remaining cinnamon sugar. Place rounds 2 inches apart on prepared pans.Bake, rotating pans once, until golden, 15 to 20 minutes. Let cool on pans for 5 minutes. Remove from pans, and let cool completely on wire racks.