Before you start, preheat oven to high grill.
Prep onion and set aside.
Heat oil in a large pot (with a lid on) on medium-high heat. Cook onion and salt for about 3 minutes, stirring occasionally, until softened. Add rice and cook for a further 1 minute, stirring constantly.
Add stock to pot and stir well. Reduce heat to low-medium, cover and gently simmer for about 18 minutes, stirring occasionally, until rice is tender. Add a splash of water if risotto becomes too dry.
Meawhile, prep courgette. Place courgette and tomatoes (vine intact) on an oven tray, drizzle with oil and season with salt and pepper. Grill on upper oven rack for 10 minutes, until tender. Remove tray from oven, sprinkle over walnuts and grill for a further 1-2 minutes, until walnuts are toasted.
Once rice is tender, add peas and lemon juice to pot and cook for a further 1 minute, until peas are tender. Remove from heat, stir through cashew cream and vegan cheesy flakes and season to taste with salt. Stir through a splash of boiling water if risotto is too thick. Prep basil.
Serve risotto topped with veggies, pesto and basil.