Brown the Butter: Add butter to a medium saucepan over medium heat. Melt the butter, stirring occasionally. Once it's melted, turn the heat to medium-low, and continue cooking the butter, stirring frequently. The butter will get foamy and bubbly, then turn a deep golden shade with a nutty, caramely aroma. Pour into a large bowl, making sure to scrape in all the brown bits from the bottom of the pan, and allow to cool in a heat-safe bowl for 40 to 45 minutes in the freezer.

Make Snickerdoodle Dough: Add the cooled brown butter to a large bowl. Whisk in the sugars. Add the eggs and vanilla, and whisk until smooth and combined, about 30-45 seconds. Fold in the dry ingredients, until completely incorporated into a dough. Cover the dough with a clean kitchen towel or plastic wrap and pop in the fridge to rest while you make the filling.

Make Cinnamon Roll Filling: In a small bowl, cream together all the cinnamon roll filling ingredients. If it's particularly warm in your kitchen, pop this in the fridge so it doesn't get melty while you make the cookie dough.

Assemble & Chill: Scoop cookie dough balls that are 65 grams in size (about 3.5 tablespoons). Flatten each dough ball and add 2 tsp of cinnamon roll filling to the center. Encase the filling in the dough completely, making sure any seams are smoothed shut, and roll the dough back into a ball. Roll in the cinnamon sugar before chilling. Chill the dough balls for at least 30 minutes in the freezer or at least 3 hours in the fridge.

Bake: Preheat your oven to 365℉. Line a few baking sheets with parchment paper. Place 5-6 cookies on a cookie sheet, allowing space between for them to spread. Bake for 10-13 minutes. The edges of the cookies will appear set and the tops will look just done. Place a round cutter around the outside of the cookies to 'scoot' or swirl them into a perfect circle.

Make Glaze: Whisk together all glaze ingredients and drizzle over the warm cookies once they've been out of the oven about 15 minutes.

Serve + Store: Enjoy cookies warm or at room temperature! Store cooled cookies in an airtight container at room temperature for 4-5 days or in the fridge for 6-7.