Preheat oven to 350°F (177°C) and adjust rack to lower-middle position.

Combine pecan halves and 1/3 cup powdered sugar in a 10-inch stainless steel skillet.

Toast in oven until fragrant, 12-15 minutes. Let cool to room temperature.

In a food processor, combine cooled pecan-sugar mixture with flour, cold butter, vanilla, salt, and cinnamon.

Pulse until pecan pieces disappear and a stiff dough forms.

Sprinkle half of the remaining powdered sugar in the skillet.

Divide dough into 20 equal portions (about 1/2 ounce each).

Roll each portion in the powdered sugar until fully coated.

Shape each coated portion into a ball.

Arrange cookies on a parchment-lined baking sheet.

Bake until puffed and firm, about 18 minutes.

Cool to room temperature directly on the sheet pan.

Sift remaining powdered sugar on top of the cooled cookies.