Preheat oven to 350 degrees F.
Place chicken in a baking pan or baking dish and squeeze lemon juice over. In a small bowl combine onion powder, thyme, ground rosemary, salt, and ground black pepper. Sprinkle over the chicken pieces, cover with foil and bake until the juices run clear and the flesh is fork tender, about 45 minutes to 1 hour. Remove foil during the last 10 to 15 minutes of baking time. Remove from oven and let rest.
Make the creole sauce while the chicken is in the oven. Heat grapeseed oil over medium heat in a sauce pot. Saute shallots and garlic until shallots turn translucent, being careful not to burn the garlic. Stir in rosemary and thyme, add crushed tomatoes, season with salt and pepper, cover and let simmer for 15 minutes. Add grape tomatoes, red and yellow bell peppers, diced onion, cayenne, and Creole seasoning, and simmer for 15 minutes more. Remove from heat and whisk in butter.
Remove chicken from oven, transfer to a platter and let rest. Spoon sauce over and sprinkle with minced parsley leaves.