Peel and slice the carrots, then trim, wash and finely slice the leeks and celery. Peel and roughly chop the onions, and the tomatoes.
Toss all the veg and the tomatoes together in a deep roasting tray, along with the unpeeled garlic cloves and a lug of olive oil, and season well.
Spread the veg into one layer and pop in the oven for 40 minutes, or until the veggies are golden and slightly caramelised.
Dissolve the stock cube in 1.25 litres of boiling water. Pick the basil leaves and finely chop the stalks.
Place the picked leaves into a pestle and mortar and bash to a paste, along with a good pinch of sea salt. When it’s completely smooth, muddle in just enough extra virgin olive oil to give it a spoonable consistency. Keep to one side.
Toss the basil stalks into the roasted veg and squeeze the garlic out of its skins into the tray. Carefully transfer the tray to the hob (or scrape the veg into a large saucepan), then add the tinned tomatoes and stock.
Gently bring to the boil over a medium heat, then reduce the heat to low and simmer for about 15 minutes, or until thickened, breaking up the tomatoes with a wooden spoon as you go.
Remove the tray or pan from the heat, then, using a hand blender or liquidiser, pulse the soup until smooth.
Return the soup to the hob over a medium heat, season to taste and stir in the alphabet pasta. Simmer for 5 minutes, or until the pasta is cooked.
Meanwhile, toast the bread and coarsely grate the cheese.
Ladle the hot soup into bowls, scatter over most of the cheese and stir it through. Top each bowl with a piece of toast, scatter over the remaining cheese, and finish with a drizzle of the basil oil. Or mix it up and add the toast and cheese to the bowl first, then add the soup and basil oil. The choice is yours!