Preheat oven to 400°F. Place the potatoes on a large baking sheet and toss with a tablespoon of the olive oil. Sprinkle with some salt and pepper. Roast for about 15 minutes, while preparing the rest of the ingredients. This step will form a nice skin on the potatoes.
Coat a large baking dish or cast-iron skillet with 1 tablespoon of the olive oil. Arrange the lemon slices and …“ of the rosemary in a single layer on the bottom of the dish or skillet.
In a large bowl, combine the remaining olive oil and rosemary with the lemon juice, garlic, salt, and pepper; add the green beans and toss to coat. Using tongs, remove the green beans and arrange them on top of the lemon slices. Remove the potatoes from the oven and arrange along the edge of the dish or skillet on top of the green beans.
Place the vegan chicken in the same bowl as the olive oil mixture and coat thoroughly. Place the chicken onto skillet and pour any of the remaining olive oil mixture over the top.
Roast in the oven for 20-30 minutes or until the green beans are tender, but still bright, and the chicken is golden brown around the edges. Place a piece of the roasted chicken on each serving plate and divide the green beans and potatoes equally. Top with the lemon slices and serve hot.