Melt the unsalted butter in a wide skillet over medium heat. Swirl frequently as it foams, sizzles, and eventually forms fragrant golden-brown milk solids at the bottom (about 5-6 minutes). Immediately pour into a heatproof bowl and let cool for 20 minutes until lukewarm. Meanwhile, spread 1/2 cup pumpkin puree across 4 layers of paper towels, pressing gently with another 4 layers on top to absorb excess moisture until thick and paste-like (approx. 1/3 cup).

In a large mixing bowl, whisk together the cooled browned butter, dark brown sugar, and granulated sugar for 2 minutes until glossy. Whisk in the blotted pumpkin puree, egg yolk, and vanilla paste until fully incorporated. In a separate bowl, whisk together all-purpose flour, cream of tartar, baking soda, ground cinnamon, pumpkin pie spice, and sea salt. Fold dry ingredients into wet with a silicone spatula just until no flour streaks remain. Cover bowl and chill dough for 45 minutes in the refrigerator.

Preheat your oven to 350°F (177°C) and line two large baking sheets with parchment paper. In a small shallow bowl, stir together the 1/3 cup granulated sugar and 1.5 tablespoons ground cinnamon. Using a 2-tablespoon cookie scoop, portion chilled dough into round balls and roll vigorously in the cinnamon sugar mixture until generously and completely coated.

Arrange coated dough balls 2.5 inches apart on prepared baking sheets. Bake for 10 to 11 minutes until edges are set and crackled while centers remain soft and slightly puffed. Remove from oven and immediately rap the baking pan firmly on the counter to encourage crinkles. Let cool on the baking sheet for 10 minutes before transferring to a wire rack.