Preheat oven to 500°F (260˚C).
Line a roasting pan with aluminum foil, then line the bottom with parchment.
Cut potatoes into 1-inch chunks and place them in a large bowl.
Drizzle with olive oil (2-3 tablespoons) and season with salt and pepper. Toss them well to coat, spread them in the roasting pan, and place the roasting pan in the oven. Set the timer for 10 minutes.
While the potatoes start to roast, wash and dry the chicken. Using a dull (not serrated) knife or metal spatula, carefully separate the chicken skin from the breast meat, trying not to tear the skin.
Season under the skin with salt, pepper, saffron and rosemary, dividing the herbs evenly between the two breasts.
Carefully slide some lemon slices under the skin, as well. Sometimes this is easier if the disks of lemon are cut in two.
Put any remaining lemon slices and rosemary sprigs in the cavity.
Truss the bird, if you like - I generally don’t. Remember, it’s a simple Sunday supper.
Once the potatoes have roasted 10 minutes, remove the roasting pan from the oven, stir the potatoes, and add a little more oil if needed. Move the potatoes to the sides a bit to make room for the chicken.
Set the chicken in the middle and drizzle with a bit of olive oil, rubbing it into the skin.
Season the chicken with salt and pepper.
Roast for 10 minutes at 500°F (260˚C), then reduce heat to 350°F (180˚C) and continue to roast for about an hour, or until juices run clear when the skin is pierced, and the legs feel loose when jiggled. NOTE: It’s good to stir the potatoes once or twice during this hour.
Place chicken on a cutting board and tent with foil to keep warm.
*Let it rest for 10 minutes (if you can wait that long).
Turn off the oven, stir potatoes, and place back in the oven to keep warm.
Carve the chicken and arrange on a warmed platter.
Add the potatoes and some peas, and you are ready to enjoy your Sunday supper.