Preheat oven to 375°F. Place tart shells on baking sheet and bake for 10 minutes.
Meanwhile, in a large skillet melt the butter over medium-high heat. Sauté the chicken with the onions, garlic and curry powder for 4–5 minutes.
Add the tomato sauce and cream and season with salt and pepper. Stir, reduce heat to medium and let simmer for 5 minutes, until thickened.
Remove from heat and stir in the cilantro and half the cheese. Divide among tart shells and sprinkle with remaining cheese.
Bake for 10–15 minutes, or long enough to melt the cheese.