Cut boneless skinless chicken breast halves into 1-inch pieces and place in a mixing bowl. In a separate bowl, combine curry powder, salt, pepper, and chili powder, then sprinkle over chicken. Toss to coat well and marinate for 1 to 2 hours if possible.

Heat 2 tablespoons of olive oil in a large frying pan over medium-high heat. Add chopped red onion and sauté for about 3-4 minutes until translucent. Stir in garlic, jalapeño, dried basil, and ground ginger, cooking for another 2-3 minutes.

Add marinated chicken pieces to the skillet. Cook for about 5-6 minutes, stirring occasionally, until chicken is no longer pink and lightly browned.

In a bowl, whisk together coconut milk, cream, and cornstarch until smooth. Pour the mixture into the skillet with the cooked chicken and stir continuously, bringing it to a simmer and allowing it to thicken for 5-10 minutes.

Once thickened, serve the Basil Chicken with Coconut Curry Sauce over hot cooked rice and top with fresh basil leaves.