For the Apples: Melt butter in a large sauté pan and add apples. Cook for 15 minutes, stirring every-so-often until apples are beginning to turn soft. Sprinkle with cinnamon. Cool completely. 

For the Salted Maple Caramel: Melt the butter in a medium saucepan over medium heat. Whisk in maple syrup and bring to a boil. Whisk constantly for about 2 minutes. Slowly pour in cream. Bring to a boil, whisking often. Boil until sauce thickens and coats the back of a spoon, (or reaches 220ºF) about 5 minutes. Remove from heat and whisk in salt. Let cool for 10 minutes.

For the Cake: Preheat oven to 350ºF and adjust rack to middle position. Place all the batter ingredients in a food processor or blender and blend until smooth. Pour batter into a buttered 9-inch springform pan. Place apples on top of cake batter in an even layer (some will overlap a bit). Pour 1/2 of the caramel over the apples. Drop spoonfuls of topping over batter. Cover loosely with a foil. 

Bake for 25 minutes and then remove the foil. Bake an additional 20 minutes until golden brown and a cake tested inserted in the middle of the cake comes out clean (the tester might have a bit of caramel on it, just make sure there isn’t any batter on the tester). Cool for 1 1/2 hours. Cut and serve with remaining caramel sauce.

For the Topping: Wipe out food processor bowl with a paper towel or cloth. Place nuts, cinnamon, honey and butter in the bowl of a food processor. Pulse until nuts are coarsely chopped and ingredients bind together.