2. Bring the chicken stock up to a boil in a saute pan. Reduce the heat and poach the chicken breasts until done, about 6-8 minutes. Remove chicken from the stock and set aside. Reserve the stock for the soup. When the chicken is cool enough to handle, cut or tear into bite sized pieces.
3. Melt the butter in a medium size saucepan over a moderate heat. Cook the chopped onions for about 10 minutes, until tender and translucent. Add the curry, ginger, and garlic, and cook for 2-3 minutes longer. Add the reserved chicken stock and coconut cream to the onion mixture. Simmer about 10 minutes. Add the diced tomatoes and lentils and bring up to a boil. Add lemon juice and salt and pepper to taste. You may add the chicken now and heat through and serve at once, sprinkled with mint. Or, you may prepare the soup up to this point and refrigerate.
To serve later: If you have made the soup ahead of time, and have cooked the chicken breasts (or have left over cooked chicken or turkey), bring the soup to a boil. Reduce heat, add the reserved shredded chicken, warm through and ladle into bowls. Thin with more stock or water as needed. Top each portion with a sprinkle of chopped mint.