Zucchini and sweet potato tian with cumin and yoghurt sauce - Gluten free

Here is a very simple side dish made with zucchini and sweet potato, and with a lovely yoghurt cumin and lemon sauce. We call it "tian" which means "baking dish" or " dish made of grilled vegetables" in occitan language. 
 
Ingredients
- 3 sweet potatoes
- 3 zucchini
- 3 tablespoons olive oil
- cumin seeds
- thyme
- salt and peper
For the sauce:
- 200 ml fulcream plain yoghurt
- 1/2 lemon juice
- 1/2 teaspoon cumin powder
- salt and pepper 

Preparation of the recipe
1- Wash the zucchini and sweet potatoes. Peel the sweet potatoes, cut them in 1 cm round slices and cook them in salted boiling water for 5-8 minutes until they get a little soft (but not too soft for them not to break into pieces). Stop the fire and drain until they are dry.
2- Cut the zucchini in 1 cm round slices too. Place them in a baking dish with the sweet potatoes one by one, alternating the sweet potato and zucchini. 
3- Pour the olive oil on top of the vegetables. Then add the cumin seeds and thyme. Bake in preheated oven (180°C) for 25-35 minutes until the zucchini is cooked.
4- Add salt and pepper.

Sauce:
5- Mix the yoghurt, cumin powder, 1/2 lemon juice and add salt and pepper. Keep in the fridge before serving. 

You can enjoy this dish warm or cold on summer days and it goes very well with grilled chicken or beef!