Combine the cranberries, ¾ cup sugar, water, orange juice, orange peel, 2 tablespoons butter, and preserves in a 1 1/2-quart saucepan. Cook over medium heat until the mixture boils. Reduce the heat to low. Cook for 15 minutes or until the filling is thick, stirring frequently. Cool for 15 minutes. Place in a food processor with a metal blade. Process the filling for 20 seconds or until smooth. Meanwhile, heat the oven to 375 degrees. Spray a 13x9-inch glass baking dish with cooking spray. Beat 3/4 cup butter and brown sugar in a large bowl at medium speed until creamy. Add the flour, baking soda and salt. Beat at low speed until mixed; beat at medium speed until smooth. Stir in the oats. Reserve 1 cup of the oat mixture. Press the remainder of the oat mixture in the bottom of the baking dish. Spread the filling evenly over the crust. Evenly crumble the remaining oat mixture over the filling; pat down lightly. Bake for 20 to 25 minutes or until golden brown. Remove from the oven and cool completely, about 2 hours. Mix the sour cream and the remaining 2 tablespoons sugar in a small bowl. Cut the dessert into squares. Top each serving with a dollop of the sour cream mixture. Store the leftover squares covered at room temperature and the leftover sour cream topping in the refrigerator. *Optional: Try cutting into smaller squares to serve as bar cookies.