1. Light the barbecue and prepare a hot side and a cooler side. Meanwhile, prep all the ingredients so you’re ready to go: peel and finely slice 3 of the garlic cloves and slice the spring onions diagonally into 1cm pieces. Halve, deseed and chop the chilli, then pick the basil leaves and finely chop the stalks. Pull off and discard the little legs from the underside of the prawns. Halve the lemon.
2. When you’re ready to cook, place a heatproof pan over a high heat. Add a splash of oil, the garlic and spring onions and cook for a few seconds until sizzling and smelling great, then add the chilli and the basil stalks. After a minute or so, add the chilli sauce and a splash of water, then cook for 5 to 10 minutes, or until thickened and reduced, stirring regularly. Place on the cool side of the grill until needed.
3. Toast the focaccia slices on both sides until crisp and golden. Halve the remaining garlic clove and rub all over the toasted focaccia, then keep warm until needed. Slice the large tomatoes into random chunks and halve and quarter the cherry tomatoes, then place in a bowl. Drizzle with the balsamic and toss to coat. Halve and destone the avocados, slice the flesh and place in a bowl, then squeeze over the lime juice and toss together. Drizzle the prawns with oil and place on the hot side of the barbecue along with the lemon, cut-side down. Grill for around 4 minutes on each side, or until crisp on the outside and cooked through – the exact timing will depend on how hot your barbecue is, so use your instincts and keep a close eye.
4. Place the garlicky focaccia onto a nice serving platter. Arrange the tomatoes and avocado on top. Drizzle everything with a little extra virgin olive oil.
5. Once cooked, transfer the prawns to the pan of glaze using tongs, then squeeze in the grilled lemon (making sure to avoid adding the pips). Toss a couple of times to coat, then carefully add to the top of the salad, drizzling the excess sauce in and around the platter. Tear over the basil leaves, then serve.
Jamie's Tip: If you have any leftover focaccia, why not try making your own croutons? Tear into thumb-sized pieces, spread out on a tray and place in the bottom of a cooling oven to dry out overnight – they’re great for sprinkling over all kinds of salads and soups. Add extra flavour by tossing with woody herbs, garlic and chilli beforehand.