Butterballs

Arrange racks in upper and lower thirds of oven; preheat oven to 350°. Toast pecans on a rimmed baking sheet until slightly darker and very fragrant, 6–8 minutes. Let cool slightly, then pulse in a food processor until very finely chopped.

Using an electric mixer on medium-high speed, beat butter and 2 Tbsp. powdered sugar in a large bowl (this can also be done by hand) until well combined. Add rum, salt, and vanilla and beat until smooth. Add flour and pecans, then beat on low speed until just combined.

Roll tablespoonfuls of dough into balls with your hands. Place on 2 parchment-lined baking sheets, spacing at least 1" apart.

Bake cookies, rotating sheets halfway through, until golden brown and firm around the edges, 15–18 minutes. Let cool, then roll in more powdered sugar, knocking off any excess.

Do Ahead: Cookies, before rolling in sugar, can be made 2 months ahead; store airtight and freeze.