Wow, this was easy to make tasted awesome. I made it for Thanksgiving. (It's best slightly warm with the warm homemade caramel on top. I found this recipe in; The potluck cookbook by Meredith, published in 2010..
Preheat oven to 325°F Grease a 13*9*2 inch baking pan; set aside.
In a bowl combine granola and 1/2 cup of the chopped walnuts. Use your fingers or a fork to combine the 1/4 cup softened butter with the granola mixture until crumbly. Set aside.
In a bowl combine flour, baking soda, cinnamon, and salt; set aside. In a bowl combine eggs, oil, granulated sugar, and the 1 cup brown sugar. Add flour mixture; stir just until combined. Fold in apples and remaining nuts (Mixture will be thick). Spoon batter into prepared pain, spreading evenly. Sprinkle with the granola mixture.
Bake for 40-55 minutes or until a wooden toothpick inserted near the center comes out clean. Cool cake in pan on wire rack for 1 hour.
For sauce, in a saucepan melt the 1/2 cup melted butter over medium heat. Stir in the 1 cup packed brown sugar and whipped cream. Bring to boiling, stirring constantly; reduce heat. Simmer, uncovered, for 5 minutes or until mixture is slightly thickened. . Remove from heat; stir in vanilla. Cool sauce about 10 minutes before serving.