In a large bowl, combine oats and butter. Add boiling water and let stand for 20 minutes.
Grease a 13x9x2-inch baking pan; set the pan aside. In a small bowl, stir together the flour, baking soda, cinnamon, and salt.
Stir oatmeal mixture. Add granulated sugar and brown sugar. Beat with an electric mixer on medium to high speed until well mixed. Add eggs, one at a time, beating well after each addition. Add flour mixture, beating on low speed until combined. Pour the batter into the prepared pan.
Bake in a 350 degree F oven for 30 to 35 minutes or until a wooden toothpick inserted in the center comes out clean. Cool cake in a pan on wire rack. Frost with Cream Cheese Frosting. Cover; store in refrigerator. Makes 12 servings.
In a medium bowl, beat cream cheese and vanilla until light and fluffy. Gradually beat in powdered sugar until mixture is a spreading consistency. Beat in 1 to 2 teaspoons milk, if needed.