Roast Chicken with Thyme and Onions

"People are always raving about chicken and rosemary, when I think chicken and fresh thyme is superior. This is so easy it's criminal, and the results are fabulous. I sometimes add four or five bulbs of green garlic if I find it at the farmers' market."
Ingredients
2 lemons
2 (2.5 pound) whole chickens
2 large onions, peeled and quartered
6 shallots, coarsely chopped
8 cloves garlic, unpeeled
 
3 tablespoons olive oil
salt and pepper to taste
1/2 cup butter, softened
8 sprigs fresh thyme
Directions
Preheat oven to 375 degrees F (190 degrees C). Lightly grease a medium baking dish.
Pierce lemons several times with a fork, and place 1 inside each chicken cavity. Arrange chickens in the center of the prepared baking dish. Place onions, shallots, and garlic around the chickens. Sprinkle vegetables with olive oil, and season with salt and pepper. Spread butter over the chickens, and line each with thyme sprigs.
Bake 20 minutes in the preheated oven. Increase temperature to 400 degrees F (200 degrees C), and continue baking 30 minutes, or until exterior of chicken is golden brown, meat is no longer pink, and juices run clear. Allow to cool about 15 minutes before serving.

Source: Allrecipes.com