1. Preheat oven to 400 degrees F.
2. Mix together the butter, garlic and onion powders, salt and pepper either in a small bowl or small food processor until thoroughly blended.
3. Gently place the butter between the breast and skin, using remaining butter to coat the entire chicken, then truss with If You Care Kitchen Twine.
4. Lay an If You Care Medium Roasting Bag on a rimmed baking sheet or roasting pan, then place the prepared chicken into the bag leaving about 2-3 inches of room from the bottom. Distribute the carrots, shallots and potatoes in bottom of the bag, top of the bag and among the chicken, then sprinkle the thyme and rosemary on the vegetables.
5. Fold the open end of the Roasting Bag upward and place in the oven for 45 minutes.
6. After 45 minutes, carefully remove the chicken from the oven and cut the Roasting Bag, folding back the edges so that the break of front of the chicken is exposed, then place back in the oven for another 25 minutes to brown. Remove the chicken from the oven and let cool for about 10 minutes, then carve and enjoy.