Chicken Makhani (Indian Butter Chicken)

Heat 1 tablespoon oil in a large saucepan over medium high heat.
Saute shallot and onion until soft and translucent.
Stir in butter, lemon juice, ginger garlic paste, 1 teaspoon garam masala, chili powder, cumin and bay leaf.
Cook, stirring, for 1 minute.
Add tomato puree and cook for 2 minutes, stirring frequently.
Stir in half-and-half and yogurt.
Reduce heat to low and simmer for 10 minutes, stirring frequently.
Season with salt, pepper and cayenne.
Remove from heat and set aside.
Heat 1 tablespoon oil in a large heavy skillt over medium heat.
Cook chicken until lightly browned, about 10 minutes.
Reduce heat and season with 1 teaspoon garam masala and cayenne.
Stir in about 1/3 of the sauce and simmer until liquid has reduced and chicken is no longer pink, about 5 minutes.
Pour the rest of the sauce into the chicken.
Mix together cornstarch and water, then stir into the sauce.
Cook for 5 to 10 minutes, or until thickened.