In a small saucepan over medium heat, melt the unsalted butter. Continue to cook, swirling the pan frequently, until the butter begins to foam and brown specks appear at the bottom of the pan. The butter will emit a fragrant, nutty aroma. Immediately remove from heat and allow it to cool for approximately 10 minutes.

In a large mixing bowl, sift together the all-purpose flour, baking powder, ground cinnamon, and salt. Set aside.

In the bowl of a stand mixer fitted with a paddle attachment, or using a hand mixer, combine the cooled brown butter, granulated sugar, and light brown sugar. Beat on medium speed until the mixture is creamy and well incorporated, approximately 2 to 3 minutes.

Add the eggs one at a time, ensuring each is fully incorporated before adding the next. Once the eggs are fully combined, add the pure vanilla extract and mix until blended.

Reduce the mixer speed to low. Gradually add the dry ingredient mixture to the wet ingredients. Mix just until the dough is fully combined; avoid overmixing to ensure a tender cookie texture.

Transfer the dough to a covered container or wrap it in plastic wrap. Refrigerate for a minimum of 1 hour, or until firm. Chilling the dough helps prevent excessive spreading during baking.

Preheat the oven to 350°F (177°C). Line baking sheets with parchment paper or silicone baking mats.

Using a medium cookie scoop or two spoons, portion the dough into balls approximately 1 to 1½ tablespoons in size. Roll each ball thoroughly in powdered sugar to ensure full coverage.

Place the coated dough balls on the prepared baking sheets, spacing them approximately 2 inches apart. Bake in the preheated oven for 10 to 12 minutes, or until the cookies are puffed, set at the edges, and feature a crinkled surface.

Allow the cookies to cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.