Butter Pecan Skillet Cookies

Place a rack in the middle of the oven; preheat to 350°. Toss pecans, maple syrup, and ½ tsp. salt in a medium bowl. Scrape onto a rimmed baking sheet lined with a silicone baking mat or parchment paper and spread nuts into a single layer. Bake until pecans are slightly darkened and syrup is dark and bubbling, 15–20 minutes. Remove from the oven and carefully toss pecans in hot syrup to coat again. Let cool on the baking sheet until caramel hardens, about 30 minutes. Break up candied pecans into pieces; discard any burned bits.

Reduce oven temperature to 325°. Generously butter a 10" cast-iron or stainless-steel skillet; line bottom with a round of parchment paper and butter parchment. Pulse flour, brown sugar, half of candied pecans, and 1¼ tsp. salt in a food processor until nuts are finely chopped. Add egg, 1 Tbsp. vanilla, and remaining 10 Tbsp. butter and process until a shaggy dough forms.

Transfer dough to a large bowl and knead a couple of times just to bring it together. Using damp hands, pat dough evenly into the skillet, extending all the way to the sides of the pan. Bake cookie until edges are golden brown and center is slightly puffed, 30–35 minutes. Let cool in the skillet for 1 hour. Invert the cookie onto a cutting board and cut into 16 wedges. Turn right side up and transfer to a wire rack set inside a rimmed baking sheet.

Whisk powdered sugar, milk, remaining ¼ tsp. salt, and remaining 1 tsp. vanilla in a small wide bowl until smooth. The glaze should be the consistency of heavy cream; thin with more milk if needed. Transfer half of the glaze to another small wide bowl (you’ll need to use 2 bowls as the glaze will start to collect crumbs and you’ll want a fresh start).

Working one at a time, lightly dip half of the wedges, top side down, into the first bowl of glaze so that only the surface is covered and no glaze drips down the sides. Use a toothpick to pop any bubbles and smooth glaze; the coating should be thin enough to see the cookie peeking through. Repeat with remaining wedges and a second bowl of glaze.

Top wedges with remaining candied pecans and let sit for 10 minutes. Sprinkle it with sanding sugar and glitter and let sit until glaze is set, about 1 hour.