Preheat the oven to 200°C.
Heat olive oil in a pan and fry the onion for 3-4 minutes, then add garlic for 1 minute.
Stir in rice for 1-2 minutes until translucent and season with salt and pepper.
Mix in squash, water, and 150ml of tomato essence, then simmer covered for 15 minutes.
Warm the remaining 150ml of tomato essence in a separate saucepan.
Roast cherry tomatoes with olive oil and seasoning on a tray for 5-6 minutes until tender.
Stir courgettes, fennel, and coriander seeds into the rice and cook for 2 minutes.
Add peas, mascarpone, and parmesan, adding extra tomato essence if needed.
Serve in bowls topped with roasted tomatoes, extra parmesan, salad leaves, and warmed tomato essence.