Step 1: Peel and core the apples. Cut each in half crosswise, then cut the halves in quarters. Place the apples in a nonreactive bowl and toss with the lemon zest and juice. Add the 1/3 cup granulated sugar, the arrowroot, and 1 teaspoon of the cinnamon and toss to mix. Taste the apple mixture for sweetness, adding more granulated sugar as necessary. Spoon the apple mixture into the cast-iron skillet and set aside.

Step 2: Combine the butter, flour, granola, remaining 1/2 cup granulated sugar, brown sugar, salt, and the remaining 1 teaspoon of cinnamon in a food processor fitted with the metal blade. Pulse until the mixture is coarse and crumbly. The butter should form pea-size pieces. Spoon the topping over the apple filling.

Step 3: Set up the grill for indirect grilling and preheat to medium-high. If using a gas grill, place all of the wood chips or chunks in the smoker box or in a smoker pouch and run the grill on high until you see smoke, then reduce the heat to medium-high. If using a charcoal grill, preheat it to medium-high, then toss all of the wood chips or chunks on the coals.

Step 4: When ready to cook, place the skillet in the center of the hot grate, away from the heat, and cover the grill. Cook the crisp until the apples are soft, the filling is bubbling, and the topping is nicely browned, 40 to 60 minutes. Let the crisp cool for a few minutes, then serve. I certainly wouldn’t say no to a scoop of apple or cinnamon ice cream on top.