Grease and flour a (14 cup) bundt pan, and set aside.
Prepare cream cheese filling
Beat the cream cheese, butter and sugar together with an electric mixer until blended and smooth. Add egg, flour and vanilla and beat until just combined. Set aside.
Prepare cake batter
Preheat oven to 350*F and bake pecans for 5-7 minutes until lightly toasted and fragrant.
Meanwhile, stir flour, both sugars, salt, baking soda and spices together in a large bowl.
Stir in eggs, then oil, apple sauce and vanilla.
Stir in apples and pecans.
Spoon two-thirds of the apple batter into the prepared pan, then spoon cream cheese filling over the apple mixture, leaving a 1 inch border around the edges of the pan.
Spoon remaining apple batter over the cream cheese filling.
Bake cake at 350*F for 1 hour to 1 hour and 15 minutes, or until a long wooden skewer inserted in the center comes out clean. Cool cake in the pan, on a wire rack about 1 hour. Remove cake from pan, and cool completely (an additional hour).
When the cake has cooled, prepare praline frosting.
Combine brown sugar, butter and milk in a saucepan and bring to a boil. Boil 1 minute (set a timer).
Remove pan from heat and add vanilla extract, then powdered sugar.
Whisk together until fully combined. If needed, pour frosting through a fine strainer to remove any powdered sugar lumps. Cool frosting slightly (about 5 minutes) until it has begun to thicken slightly, but is still easily pour-able.
Pour over cake, as desired. Garnish with pecans, if desired.