Combine sesame oil, ginger, and garlic in a medium bowl. Add onions and yellow bell pepper; stir thoroughly. Add curry powder, curry paste, cumin, soy sauce, salt, and brown sugar. Mix thoroughly and set aside.

Place sweet potatoes, eggplant, and green beans in slow cooker. Remove tough base and outer layers of lemongrass; cut each stalk into 3 pieces and crush slightly with the flat edge of a knife. Layer stalks on top of vegetables.

In a nonstick skillet coated with cooking spray, brown chicken drumsticks over medium-high heat until golden on each side. Add chicken to slow cooker.

Spread onion-curry mixture over vegetables and chicken. Pour in coconut milk. Cover and cook on low for 6–8 hours or until vegetables are tender and chicken is cooked. Forty-five minutes prior to serving, add pineapple juice and frozen peas. Add salt if needed. Stir gently and re-cover. To serve, garnish with fresh basil.