Whisk the olive oil with the juice of 1 1/2 lemons, the salt, pepper, cumin and the leaves of the thyme. Slice the remaining 1 1/2 lemons and place in a casserole in a single layer. Cover with the onion, peeled and sliced, and then the garlic, peeled and roughly chopped. Cut the backbone from the chicken (with two lengthwise cuts, one on either side of the bone). Spread the chicken and lay it skin-side down in the casserole. Brush with half the olive oil mixture, turn it over, pat the skin dry with a paper towel, and brush with the remaining mixture, Pour the wine around the chicken. Roast in a 400° oven, basting occasionally, for 1 1/2 hours or until tender. Remove from oven and allow to rest for 15 minutes.

Cut the chicken into pieces and serve.