[Greek] How to cook Vegetarian lentil and eggplant moussaka

Ingredients
- 1 tbsp olive oil
- 1 small red onion, finely chopped
- 2 cloves garlic, finely chopped
- 1½ tbsp picked lemon thyme leaves
- 400 g tin tomatoes with herbs
- 400 g tin lentils, drained and rinsed
- ¼ cup picked oregano leaves
- salt and black pepper
- 140 g chargrilled eggplant slices, cut into 3 cm pieces
- 80 g fresh ricotta
- 80 ml (â…“ cup) Greek yoghurt
- 1 egg
- mixed green leaves, to serve