Preheat oven to 375° F. Defrost the vegetables in a microwave for about 3 minutes.
Cut 2 piecrusts into quarters, to yield 8 equal pieces. Coat the inside of 4 small aluminum-foil pans (4 1/2 inches in diameter, 1 1/4 inches deep) or 4 ramekins with vegetable cooking spray. Line the bottom of each with a quarter of crust, molding it with your fingers to fit.
In a large bowl, stir together the soup and milk; add the remaining ingredients. Spoon about 2/3 cup of the mixture into each pan or ramekin. Top each with a piecrust quarter. Pinch the edges together and cut vents in the top.
Place on a baking sheet and bake for 35 to 45 minutes or until golden brown.