The night before you plan on cooking the chicken, take it out of its packaging and remove all the extra bits inside the cavity. Prepare a baking sheet with a paper towel layer. Place the chicken on top of the paper towel. Generously salt the entire chicken, outside and inside. Put the chicken in the refrigerator, uncovered, for at least 18 hours.

Take the chicken out of the refrigerator. Use the paper towel to clean up any liquid or blood that might have ended up on the pan while it rested. Preheat an oven to 375°F.

Place the potatoes, fennel, and shallots in a large bowl with olive oil. Toss until all the vegetables are coated. Prepare a baking sheet with aluminum foil and nonstick spray. Transfer the oiled vegetables on the baking sheet and season with salt and pepper.

Fill the cavity of the chicken with the garlic and rosemary. Heavily season the chicken with black pepper. Place, breast side up, on top of the vegetables.

Bake for 1 ½ to 2 hours, or until the internal temperature reads 165°F. Remove from the oven and cover with aluminum foil. Let it rest for 10 minutes before cutting to serve.