1. Preheat the oven to 350°F. 
2. Remove all packaging from the chicken and pat the chicken dry with paper towels. 
3. Place the onion and garlic in the bottom of a Dutch oven, large oven-safe skillet, baking pan, or roasting pan. 
4. Place the chicken in the pan on top of the onions. 
5. Using your hands, rub the chicken all over with the oil. Sprinkle it with the salt and pepper. 
6. If using the lemon and herbs, tuck those into the cavity of the chicken. (Optional: Tuck the wings underneath the chicken and use kitchen twine to tie the legs together.) 
7. Add the ½ cup broth or water to the pan around the chicken, and place the chicken in the oven, uncovered. Bake for 20 minutes per pound or until an instant-read thermometer inserted into the thickest part of the breast reads 165°F. For example, for a 4-pound chicken, the bake time will be about 1 hour and 20 minutes. 
8. Start checking the chicken for doneness 10-15 minutes before the estimated time is up.
9. When the chicken is done, remove the chicken to a cutting board, cover loosely with foil and allow it to rest for 10 minutes before slicing. 
10. Slice or pull the chicken from the bones and serve it with the optional gravy, if desired.
11. Store leftovers in an airtight container in the fridge for up to 4 days or freeze for up to 3 months.

To Make The Optional Gravy:

1. Remove the onions and garlic from the pan (these can be served alongside the chicken, if desired, or saved to add to the bones if making bone broth).
2. Pour the drippings from the pan into a small measuring cup and allow to sit for a few minutes. Once the fat and watery layer (the drippings) have separated, use a measuring spoon to remove and discard as much of the fat as possible from the top of the drippings. Measure out ⅓ cup of the drippings. 
3. Place the pan used to roast the chicken over medium heat (or use a saucepan). Add the ⅓ cup drippings. 
4. When the drippings are hot, sprinkle the 2 tablespoons flour over the drippings and whisk until it makes a paste-like mixture. 
5. Continue whisking until the flour mixture is a golden brown color, about 2 minutes. 
6. Slowly add the 1 cup broth while whisking constantly.
7. Continue cooking the gravy until it thickens, 5 to 7 minutes. If the gravy is too thick, add a little more broth. If the gravy is too thin, continue to cook for another 2-3 minutes.
8. Add the salt and pepper, then taste and adjust seasonings as desired. Serve gravy with the chicken.