The foil - without which the potatoes would stick to my pan - is Bacofoil non-stick, which works well.
2 chicken thighs
2 medium potatoes, peeled, sliced, rinsed, and patted dry
Unpeeled garlic cloves (as many as you like)
1 fennel bulb, tough and discoloured outer layers removed, sliced
1 preserved lemon, roughly chopped
Coat the chicken in a little oil (with your hands), then spread the harissa all over (with a spoon or knife). Put the pieces in a non-stick roasting tin, or in an ordinary tin lined with non-stick foil. Put in the potatoes and garlic too, and toss them in oil. Season everything, and bake at gas mark 6/200C.
After about 40 minutes, toss the fennel slices with the potatoes and garlic. Cook for another 30 minutes or so, until the potatoes and fennel are tender. About 10 minutes from the end, toss the preserved lemon pieces with the potato, garlic and fennel mixture.