Put a rimmed baking sheet into a cold oven. With baking sheet inside, preheat oven to 425.
In a medium bowl, combine chopped potatoes with 2 tablespoons melted vegan butter and ½ teaspoon garlic salt.
Once oven is preheated, remove hot pan, line with parchment paper, and spread prepared potatoes on it, keeping them on the outer edges of the pan as much as possible. Bake for 15 minutes.
In a large bowl, combine cut chicken, green beans, and garlic cloves. Toss with remaining 3 tablespoons melted vegan butter and all remaining seasonings (parsley, garlic powder, thyme, pepper, and remaining 1 ½ teaspoons garlic salt) until well combined.
Take potatoes out of the oven. Don't stir the potatoes - let them keep getting crispy cut side down in the middle of the pan. Lay the chicken breast in the middle of the pan. Spread the green beans on top of the potatoes. Return to oven for 20-25 minutes.
Sheet pan is done when chicken is cooked through (no pink inside), potatoes are crispy, and green beans are tender and slightly crispy. Remove roasted garlic cloves. Toss to combine and serve, drizzled with Garlic Ranch if desired.
