Preheat the oven to 400°F. Spray a baking tray with olive oil spray and set aside.
In a large bowl, whisk together the egg, lemon juice, 2 teaspoons garlic, parsley, salt and pepper. Set your chicken in the egg mixture.
In another bowl, combine the breadcrumbs and the parmesan cheese. Roll the chicken in the breadcrumbs, pressing lightly to coat. Place chicken onto the baking sheet and lightly spray with olive oil. Arrange the potatoes around the chicken.
In a small bowl, mix the melted butter, garlic and salt to taste. Drizzle half of the butter mixture over the potatoes, then bake for 15 minutes.
Remove the baking tray and flip each chicken breast. Add the green beans around the chicken and potatoes, then drizzle the remaining garlic butter over the top. Return to the oven and broil for 10 minutes, or until chicken is golden and crisp, and the potatoes are tender. Add fresh lemon slices and serve immediately.