Cut the tops off the tomatoes (keep the tops as they will be the lid) and scoop out the flesh.
A food mill is a useful gadget here: plop the pulp onto the plate and crush the contents into a bowl. This removes the pips and hard bits that can form near the stalk. Or run the tomatoes through a fine sieve with a wooden spoon (less fun than using a mill).
Shred the basil leaves finely and stir these into the juice with a scant teaspoon of salt, 2 tablespoons of olive oil and a couple of grinds of black pepper.
Taste it; the rice is going to absorb and knock back the flavour, so you want it to be properly seasoned. Anna’s method is to soak the rice in this mixture for at least 1 hour before spooning it into the tomato shells, but I have found my rice doesn’t cook very evenly when I do this, so I cheat and simmer the tomato-rice mix in a pan for 6 minutes and let it cool a little before I distribute it evenly among the 4 tomato shells, making sure not to overfill any of them.
Tuck a small garlic clove into each tomato and top with the lid.
Place them in a baking dish and drizzle everything with olive oil.
Bake in the oven for 50–60 minutes.
Remove from the oven and once they are cool, remove the garlic cloves. Served warm or at room temperature; they taste even better if you can let them sit overnight.