Fry the shallots in olive oil until nicely soft and brown. They should start to smell sweet, slightly smokey or caramelised.
Cut the tomatoes in half, cut away the green ends and discard the juice and seeds. Chop the flesh finely, add the shallots and basil, season with salt and pepper. v
Cut the halloumi cheese into even slices, then, using dressing rings, cut 4 round bases out of them (you might have to do a little patchwork, if your cheese is not big enough for your rings). Keeping the rings on the bases, divide the tomato tartare between them and even the surface out.
Carefully remove the rings, drizzle with some olive oil and balsamico and top with a basil leaf.