Preheat oven to 400°F. In large saucepan, heat oil over medium heat; cook beef for about 7 or 8 minutes or until browned. Remove from pan; set aside.
Drain all but 1 tbsp fat from pan; sauté garlic, onion, jalapeno, carrots and celery for 5 or 6 minutes or until vegetables are golden and tender-crisp. Stir in broth, salsa, tomato paste, chili powder, salt and pepper; bring to simmer. Return beef to pan; cover and cook for 40 minutes or until beef is tender.
Whisk cornstarch with 1/4 cup water; stir into saucepan. Bring to boil; reduce heat and simmer for 10 to 15 minutes or until mixture is thickened. Remove from heat; stir in 1 cup of the cheese. Divide evenly among four 1-cup ramekins.
Cut out 4 rounds from pastry, each 1 inch larger in diameter than the top of ramekin. Place rounds over top of ramekins, pressing down edges to adhere. Whisk egg with 1 tsp water; brush over top of pastry. Using tip of sharp knife, cut steam vents. Sprinkle remaining cheese evenly over top of pastry. Bake for about 20 minutes or until pastry is flaky and golden, and cheese is melted.