Heat oven to 375 degrees F. Spray 24 mini muffin cups with cooking spray.

Unroll pie crusts on cutting board. With 2 1/2 inch round cutter, cut 12 rounds from each crust. Press one round into the bottom and up sides of each muffin cup.

Place 1 tablespoon of Swiss cheese in each cup. Top with a few onion slices. In a 2 cup measuring cup, beat eggs, parsley, milk and salt with fork until well blended. Pour mixture into crusts, filling to within 1/4 inch of top.

Bake 25 - 30 minutes until golden and filling is set. Cool 2 minutes. With tip of knife, lift quiches from muffin cups and serve warm.