Heat your oven to 200°C/Fan 180°C/Gas 6. Halve the gem squash and scoop out the seeds with a
spoon. Chop the squash into 2cm chunks (you can eat the skin, so no need to peel). Tumble the squash onto a baking tray. Drizzle over 1 tbsp olive oil and some salt and pepper. Slide into the oven and roast for 30 mins till golden and softened. Toss half way through.
Finely slice the sundried tomatoes. Pop them into a jug. Crumble in the stock cube. Pour in 500ml boiling water and leave the tomatoes to soften.
Peel and finely chop the onion. Peel and crush one of the garlic cloves. Cut half the heirloom tomatoes into small chunks. Heat a large pan for 2 mins. Drizzle in ½ tbsp olive oil. Add the onion, season and cook for 5 mins till softened. Add the garlic and chopped tomatoes. Cook for 3 mins till the tomatoes have broken down a little.
Tip the risotto rice into the pan and stir together to coat the grains in the tomatoey oil. Pour in the
sundried tomatoes along with the water. Stir well. Turn the heat to low and pop on a lid. Cook for 20 mins, till the water has been absorbed and the rice is tender. Stir every now and then, adding a little more water if necessary.
While the risotto is cooking, make the walnut pesto. Set a frying pan on the heat. Throw in the walnuts and toast them for 2-3 mins till slightly darkened and nutty smelling. Tip onto a chopping board. When cooled, finely chop them.
Pull the leaves from the thyme. Peel and grate the remaining garlic. Zest the lemon and squeeze the juice from it. Add to the bowl with ½ tbsp oil. Mix well with some seasoning. You can throw everything into a food processor if you have one.
Halve and quarter the remaining heirloom tomatoes, depending on their size. Roughly chop the spinach leaves.
Remove the roasted squash from the oven. Taste the risotto. The grains should be soft with a slight bite. Season a little. Tip in most of the roasted squash and all of the chopped spinach. Stir together gently. Pop on the lid for 1 min to allow the spinach to wilt.
Spoon the risotto into warm bowls. Top with the remaining roasted squash, heirloom tomatoes and a large spoonful of the walnut pesto. Cut the lemon half into wedges and squeeze over to taste.