I have to confess I made this on my stove, but it is really good. I skipped the sour cream and the cumin and used a lot more jalapenos and cilantro. Recipe posted as written. Courtesy of foodfanatic.com.
Soak the hickory chips in water for at least 30 minutes before using.
Meanwhile, prepare the grill for indirect heat. If using a gas grill, turn burners on one side to high and leave burners on other side off. If using a charcoal grill, bank the charcoal up against one side of the grill.
Using an 8 to 10 inch cast iron skillet, place the shredded cheese evenly across the bottom of the skillet.
Place the hickory chips directly on the coals and wait for the smoke to appear. If using a gas grill, make an aluminum foil pouch for the hickory chips. Seal pouch, but poke several holes in the top to allow smoke to escape.
Once hickory chips are smoking, place the cast iron skillet on the opposite side from the charcoal or lit burners. Cover grill and cook for approximately 30 minutes or until cheese has fully melted. Check on the cheese occasionally and rotate the skillet as needed.
Meanwhile, place the olive oil, diced onion, and diced jalapeno in a medium fry pan. Cook over medium-high heat for 5 to 6 minutes, or until onions begin to turn translucent. Add diced garlic and cook for 2 more minutes, stirring frequently.
Whisk the flour and cumin into the fry pan and cook for about 45 seconds, stirring constantly. Add the milk and whisk until mixture is well combined. Cook for 3 to 4 more minutes, or until mixture begins to thicken slightly.
Remove from the heat and stir in the cilantro, diced tomatoes, and diced chiles. Set aside mixture.
Once the cheese has melted fully, add the sour cream and sauteed onion mixture. Stir together until fully combined. Transfer mixture to a serving bowl and garnish with freshly cracked black pepper. Serve hot with tortilla chips.