Brown the butter: In a large skillet on the stovetop, melt butter over medium/low heat. Once melted, increase heat to medium and cook, stirring frequently as the butter begins to pop/bubble and fiz. Stir/swirl frequently, scraping the bottom of the pan until the sizzling slows and you notice lots of brown specks forming.

Remove from heat and pour into a large heat-proof bowl. Allow to cool completely before proceeding with recipe.

Make the cookie dough: Preheat oven to 350F (175C) and line baking sheets with parchment paper. Set aside.

In a large mixing bowl, stir together browned (cooled) butter and sugars until combined.

Add eggs and vanilla extract and stir well.

In a separate, medium-sized mixing bowl, whisk together flour, cream of tartar, baking soda, salt, and cinnamon.

Gradually (in 4 or 5 parts) stir flour mixture into butter mixture until completely combined. The dough will seem stiff, this is normal.

In a separate small bowl, whisk together sugar and cinnamon for rolling.

Roll cookie dough into 1 ½ Tablespoon-sized balls and roll each ball through cinnamon/sugar mixture, coating evenly. Place cookies on prepared baking sheet, spacing at least 2” (5cm) apart.

Bake in 350F (175C) oven for 9-11 minutes. The centers of the cookies may appear slightly under-done when removing from oven, this is fine, allow the cookies to cool completely on the baking sheet where they’ll finish cooking through before enjoying.