Stuffed Poblano Peppers

Blister peppers on all sides under broiler or on grill until blackened. Place in heatproof glass bowl. Cover tightly with plastic wrap and set aside for 20 minutes. Peel and seed peppers by cutting a slit down the pepper from top to bottom to open. Melt butter in saute pan and add vegetable oil. Turn heat to medium. Add carrots, celery, and onions; cook until wilted but not brown. Add garlic and saute 2 minutes. Add chili powder, cumin, paprika, salt, and pepper. Stir in rice, tomatoes, and chicken stock. Bring to a boil. Reduce heat, cover and simmer until all liquid is absorbed, about 20-25 minutes. Remove from heat. Cover pan with a paper towel and replace lid. Steam for 5 minutes. Remove towel and lid and let stand for 5 minutes. Stuff peppers with filling; place on greased baking pan, seam side up. Sprinkle each pepper with 1/4 cup shredded Pepper-Jack cheese. Place under broiler until cheese melts and bubbles.