Caramelized Sweet Vidalia Onion Tart Recipe - Paula Deen

Ingredients

• 1/2 (14.1-ounce) package refrigerated piecrusts
• 1/4 cup Butter
• 5 large Vidalia onions , thinly sliced
• 2 tablespoons balsamic vinegar
• 1 (8-ounce) package cream cheese , softened
• 1 (4-ounce) package goat cheese , softened
• 1 1/2 cups shredded Gruyère cheese , divided
• 2 egg yolks , lightly beaten
• 1/4 teaspoon salt
• 1/4 teaspoon ground black pepper