Sweat the aromatics. Heat the olive oil in a large stockpot over a medium flame. Add the onion, carrot, and celery, and cook for 5 to 6 minutes, stirring occasionally. You'll know it's ready when the onion turns translucent and the kitchen smells sweet and savoury.

Bloom the garlic. Stir in the crushed garlic and dried oregano, and cook for another minute. The garlic should become fragrant — if you catch a whiff of raw garlic, give it another 30 seconds.

Build the soup base. Pour in the chopped tomatoes and the chicken stock. Add the sugar, a generous pinch of salt, and a few cracks of black pepper. Bring the mixture to a gentle boil — you'll see lazy bubbles breaking the surface — then reduce the heat to low.

Simmer and blend. Let the soup simmer uncovered for 15 minutes. The colour will deepen to a rich brick-red, and the liquid will thicken slightly. Remove from the heat and use an immersion blender to whizz it until completely smooth. If you prefer a chunkier texture, only blitz half of it.

Finish the soup. Stir in the double cream if using, and taste for seasoning. The soup should be silky and bright, with a gentle sweetness from the carrot. Keep it on the lowest heat while you make the sandwiches.

Butter the bread. Spread a thin, even layer of softened butter on one side of each bread slice. I used to struggle with this dish until I discovered that buttering the bread instead of the pan gives a far more even, golden crust.

Assemble the sandwiches. Place four slices of bread, buttered side down, on a clean work surface. Divide the grated cheese evenly among them, then top with the remaining bread slices, buttered side up.

Toast to perfection. Heat a large non-stick frying pan or a griddle over a medium heat. Place the sandwiches in the pan (you may need to work in batches). Cook for 2 to 3 minutes on each side. The bread should turn deep golden brown and feel firm to the touch, and you'll hear a satisfying sizzle. The cheese should be fully melted — if it's oozing out the sides, you've nailed it.

Rest and serve. Let the sandwiches rest on a cutting board for 30 seconds before slicing in half. Ladle the hot soup into bowls and serve the grilled cheese alongside for dipping.