Soak the Roman pot in water for 15 minutes before use.
Cut the eggplant into roughly 2cm cubes. Place in a bowl, mix with a bit of salt, and let sit for 15 minutes to draw out water and bitter flavors.
Mix the oil, sweet paprika, hot paprika, and salt in a small bowl to make the marinade.
Wash and dry the chicken legs, then coat thoroughly with the paprika-oil mixture. Refrigerate while preparing vegetables.
Cut the bell peppers and zucchini into bite-sized pieces. Cut the onions into coarse strips. Slice the garlic thinly.
Squeeze the eggplant well by hand to drain out excess moisture and discard the liquid.
Add the drained eggplant, peppers, zucchini, onions, and garlic to the Roman pot.
Add the vegetable or chicken broth, herbs de Provence (or fresh or dried rosemary and thyme), tomatoes, a splash of water or dry white wine, salt and pepper to taste, and optional mushrooms and olives. Mix well but do not add too much liquid, as the vegetables will release their own moisture during cooking.
Place the marinated chicken legs on top of the vegetables, skin-side up.
Cover the Roman pot with its lid and place the entire pot in a cold oven.
Set the oven to 220°C (428°F) with top and bottom heat. Bake for 60 minutes with the lid on.
Remove the lid carefully and bake for 10-15 minutes more until the chicken skin is crispy and golden.
The chicken is done when the internal temperature at the thickest part of the thigh reaches 74°C (165°F).