Heat oven to 375°F. Spray 24 mini muffin cups with cooking spray.
Remove pie crusts from pouches; place flat on cutting board or pastry cloth. With 2 1/2-inch round cutter, cut 12 rounds from each crust. Press 1 pie crust round into bottom and up sides of each muffin cup.
Place 1 tablespoon cheese in each cup. Top each with a few onion slices and pimiento pieces. In 2-cup measuring cup, beat eggs, milk, salt and nutmeg with fork until well blended. Pour mixture into crusts, filling to within 1/4 inch of top.
Bake 25 to 30 minutes or until golden brown. Cool 2 minutes. With tip of knife, lift quiches from cups. Serve warm.