Preheat the oven to 250°C, 475 F, gas 9.
Peel the garlic. Slice the cloves in half.
Quarter the tomatoes. Remove the seeds and chop.
Remove the basil leaves from the stem. Set a few aside for garnishing. Coarsely chop the rest.
Mix the basil leaves with the tomatoes and lemon juice. Season with salt and pepper to taste.
Toast the bread slices in the oven (lay directly on a rack) for approximately 2 minutes until golden brown.
Rub the hot slices with the garlic and drizzle with olive oil. Place some tomatoes on top of each slice. Garnish with the reserved basil leaves and serve.