Place the potatoes and carrots in the bottom of the crock pot. Drizzle with 1 tablespoon olive oil and season with 1 teaspoon salt, 1/2 teaspoon black pepper, and 1 teaspoon garlic powder. Toss to coat.

Pat the chicken dry with paper towels. Stuff the cavity with the quartered onion, lemon, and bay leaf.

Place the chicken on top of the vegetables.

Drizzle 1 tablespoon olive oil over the chicken skin. Carefully loosen the breast skin and rub the remaining tablespoon of olive oil underneath.

Combine the remaining salt, pepper, garlic powder, onion powder, and smoked paprika. Rub the seasoning mixture all over the chicken and underneath the skin.

Cover and cook on LOW for 7–8 hours or HIGH for approximately 4 hours, until the thickest part of the thigh and breast reaches 165°F.

For crispy skin, transfer the cooked chicken to a sheet pan, drizzle with additional olive oil, and broil for a couple of minutes until golden and crispy. Watch carefully to prevent burning.

Let the chicken rest for 10 minutes. Remove and discard the onion, lemon, and bay leaf before carving.

To make gravy, melt butter in a saucepan over medium heat. Whisk in flour until smooth. Strain the crock pot juices and slowly whisk them into the butter mixture. Cook until thickened. Add chicken broth if needed to reach your desired consistency. Season with salt and pepper.

Serve the carved chicken with the potatoes, carrots, and gravy.