Combine the plum tomato, black olive and seasoning in a mixing bowl and stir well to combine. Cover and chill until ready to assemble the tartines. Preheat the oven to 200°C.
Brush both sides of the slices of baguette with olive oil. Arrange on baking trays and bake for 8-10 minutes, turning once until golden brown in colour. Remove from the oven, then remove the tomato topping from the fridge.
Stir in the chopped basil then spoon on top of the baguette slices. Garnish each with a basil leaf then arrange on serving platters.