In a medium bowl, toss the tomatoes with the basil and season with salt and pepper, to taste. Set aside while you prepare the prawns.
Divide the prawns between 2 (8 or 9-inch) pie pans and pat them completely dry with a paper towel. Arrange the prawns so they lay flat and are evenly spaced in the pans.
Heat 2 large pans over medium heat, or do this in 2 batches if you only have 1 pan. Season 1 side of the prawns with salt and pepper. Add enough oil to lightly film the bottom of the pan and turn the heat up to high. Invert the pan of prawns so they all fall into the pan at once. Saute the prawns, undisturbed, until they turn golden brown on the bottom, about 2 minutes. Add a bit more oil and 1/2 the garlic to each pan. Turn the heat off and turn the prawns over with tongs. Cook the prawns for 1 minute in the residual heat of the pans. Transfer the prawns to the bowl with the tomato mixture and toss to combine. Divide the prawns among 4 plates or a serving platter and serve hot or at room temperature.