For the filling, in a medium sized bowl, mix apples with lemon juice, vanilla, brown sugar, cinnamon, cornstarch, and salt until the apples are completely coated.
Butter an 8 x 8 baking dish.
Pour the apple filling into the baking dish.
For the topping, in a separate bowl, whisk together the flour, brown sugar, cinnamon, nutmeg and salt.
Add the cold cubed butter to the dry topping and use your hands to mix until the butter and dry topping come together in a pebbly, crumble texture mixture.
Add a third of the topping over the apple filling and mix with the filling slightly.
Sprinkle the remaining topping over the apple filling.
Add a 1⁄2 cup of the all-purpose blend of pellets to the Woodfire Grill pellet hopper.
Set the Woodfire Grill to the Air Crisp and Woodfire Technology setting for 45 minutes and set to 325 degrees Fahrenheit.
Let the Woodfire Grill Cycle through the preheating and pellet ignition.
Once the Woodfire Grill states to ADD FOOD, place your dish onto the grill grate and close the lid.
Air Crisp for 40 to 45 minutes, until the streusel topping is a dark golden brown.
Remove dish from the Woodfire Grill and let rest for 10 to 15 minutes before serving.
Serve with vanilla ice cream and enjoy!