Preheat the grill to high. Remove the steaks from the refrigerator and let stand at room temperature for 20 minutes before grilling. Meanwhile, combine the cumin, salt, and pepper in a small bowl. Liberally season both sides of each filet with the spice mixture. Grill the filets for about 3 to 4 minutes on each side for medium doneness.
Meanwhile, preheat the broiler. Remove the steaks from the grill onto a baking sheet, and top each with a slice of the cheese. Place under the broiler until cheese is golden brown and soft. Alternatively, use a blow torch or kitchen torch to brown the cheese. Ladle the sauce onto each plate, place the steak in the center, and garnish with chopped cilantro.
Heat the oil in a medium saucepan over medium-high heat. Add the onions and garlic, and cook until soft. Add the chiles and stock, and bring to a simmer for 20 to 25 minutes, or until the chiles are soft. Transfer the mixture to a food processor and process until smooth.
Strain the mixture into a saute pan that has been set on high heat for a few minutes, and cook the sauce until slightly thick. Remove from the heat and stir in the creme fraiche and maple syrup. Season with salt and pepper, to taste.