Step 1

Preheat your pellet grill to 325° according to factory directions.

Step 2

Mix together the oil, sugar, egg, sour cream, baking soda, baking powder, baking soda, vanilla, and flour in a mixer until well combined. Add in diced apples and fold in.

Step 3

Spread batter into a prepared 9x13 baking pan. Mix together streusel ingredients by hand until crumbly, and sprinkle evenly over the top of the batter.

Step 4

If you have a second rack in your pellet grill, place the cake on the top rack. If you do not have a top rack, invert a 9x13 high-sided empty pan and place on the rack, and then place the batter-filled pan on top to create some additional space between the bottom of the cake pan and the fire below.

Step 5

Bake in a preheated 325° pellet grill or oven for 35-45 minutes, or until a tester comes out with only moist crumbs.

Step 6

Cool for 10 minutes, and serve warm if possible.