Preheat your oven to 350 degrees Fahrenheit and grease a 13×9 inch baking pan.
In a large bowl, beat together the brown sugar, granulated sugar, and canola oil.
Add the eggs one at a time, beating thoroughly after each addition.
In a separate bowl, whisk together the flour, baking soda, cinnamon, nutmeg, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Fold in the chopped apples, walnuts, and vanilla extract until evenly distributed.
Pour the batter into the prepared pan and spread evenly.
Bake for 60 minutes or until a toothpick inserted into the center comes out clean.
Prepare the glaze by simmering the butter and heavy cream in a small saucepan until slightly thickened.
Drizzle the hot caramel mixture over the cake shortly after removing it from the oven.