Preheat oven to 500 F with a baking sheet inside.
When oven is hot, remove baking sheet and spray with cooking spray. Spread the baby potatoes into one layer and roast for 10 minutes.
While potatoes are roasting, mix 1/2 cup of olive oil, minced garlic, salt and pepper, cayenne pepper, parsley, and lemon juice in a medium sized bowl. Reserve.
Season chicken breasts with salt and pepper. In a large skillet, over medium high heat, heat 2 tablespoons of olive oil and brown the chicken breasts on both sides, about 4-5 minutes per side.
Once potatoes are done roasting for 10 minutes, add the chicken breasts to the baking sheet an dpour the marinade into the chicken and potatoes, tossing so everything is nicely coated. Return the baking sheet to the oven and roast for another 10-15 minutes or until chicken is cooked through (165 F) and ptoatoes are tender.
Sprinkle with fresh parsley and serve.