Preheat the oven to 400 degrees.
Place a baking wire rack on a sheet pan and arrange the bacon on the rack in a single layer. Bake for 15 to 25 minutes, until the bacon is browned and crisp. Drain on paper towels and set aside.
Whisk together the mayonnaise, basil, salt, pepper, lemon juice, olive oil and garlic.
Toast the bread slices. Spread the mayonnaise mixture on the top of 1 slice of bread. Place the sliced tomato and bacon on top of the second bread slice. Place the slice with the mayonaisse on top. Cut in half and serve.