Preheat the oven to 400° F (200° C)
Mix cream (or sour cream) with pesto and lemon juice Salt and pepper to taste.
Season the chicken thighs with salt and pepper, and fry in butter until they turn a nice golden brown.
Place the chicken in a greased suitable baking dish, and pour in the cream mixture.
Chop the leek and cherry tomatoes Chop the cauliflower into small florets Top chicken with leek, tomatoes, and cauliflower.
Sprinkle cheese on top and bake in the middle of the oven for at least 30 minutes or until the chicken is fully cooked If the casserole is at risk of burning before it's done, cover it with a piece of aluminum foil, lower the heat and let cook for a little longer.