Sour Cream Apple Pie with Walnut Streusel

Ingredients

• 1 and 1/4 cups sour cream
• 3/4 cup sugar
• 1/4 cup flour
• 1/4 teaspoon salt
• 1 egg
• 2 teaspoons Gefen Vanilla Extract
• 3 Granny Smith apples, sliced thin (1/8-inch thick)
• 3 Cortland apples, sliced thin (1/8-inch thick)
• 1 Gala or McIntosh apple, sliced thin (1/8-inch thick)
• 3/4 cup chopped walnuts
• 3/4 cup flour
• 1/3 cup sugar
• 1/3 cup brown sugar
• 1 teaspoon ground cinnamon
• pinch of salt
• 8 tablespoons (1 stick) butter, melted
• store bought caramel sauce
• 2 frozen 9-inch deep pie crusts (not graham cracker crust)