Preheat the oven to 220°C/200°C/gas 7.
Put the new or baby potatoes in a roasting tin and toss with 2 tbsp oil, the thyme and some seasoning. Roast for 20 mins.
Take the tin out of the oven, add the leeks and spinach, and gently combine them with the potatoes.
Drizzle with the remaining oil, squeeze over the lemon and dot with goat’s cheese.
Return to the oven for another 20 mins, until the veg is soft and caramelised.
To serve, drizzle with the pesto, scatter with torn basil or mint (if using) and drizzle with another squeeze of lemon.
