Slice the baguettes into 1/2-inch slices and brush each side with olive oil.
Grill the bread slices for a couple minutes on each side, on an electric grill, grill pan, or grill. Alternatively, bake the bread slices in the oven at 360°F (180°C) for about 10-12 minutes until crispy on the outside and slightly golden.
Add a thin slice of Provolone cheese to each piece of toast.
Slice the tomatoes thinly and sprinkle some salt on top.
Top the crostini with tomatoes and fresh basil.
Add the prosciutto on top.