The dough can be made up to 3 days ahead, or you can freeze thoroughly cooked, baked shortbreads in an airtight container for up to 2 weeks. So you can make these ahead of time if you are serving at a party.
Preheat oven to 350°. Bake pecans in a single layer in a shallow pan 8 to 10 minutes or until toasted and fragrant, stirring halfway through. Cool completely (about 20 minutes). Reduce oven temperature to 325°.
Process cheese and butter in a food processor 10 to 15 seconds or until creamy stopping to scrape down the sides as needed. Add flour and the next 3 ingredients; pulse 9 to 10 times or until the mixture is crumbly. Add toasted pecans, pulse 4 to 5 times or until combined. Add half and half, and process 10 to 15 seconds or until the mixture forms moist clumps.
Transfer mixture onto plastic wrap on a flat surface; gather dough into a ball, and flatten into a 1 inch thick disk. Wrap in plastic wrap and chill 1 hour until firm, or seal wrapped dough in a zip-top plastiac freezer bag and chill up to 3 days.
Turn dough out onto a floured surface. Roll to 1/8 to 1/4 inch thickness. Cut with 1 1/2 and 2 inch cookie cutters. Place on parchment paper-lined baking sheets.
Bake at 325° for 16 to 18 minutes or until golden brown. Transfer to a wire rack; let cool 15 minutes.