Soak the tomatoes in warm water for 10 minutes. Peel and finely dice the garlic. Rinse the basil and pat dry. Set aside a few leaves for garnish, and finely chop the rest.
Drain the tomatoe and finely chop. Finely grate the feta cheese, then mix with the pastry cream. Stir until smooth, then add the tomatoes, garlic, and basil. Set aside, and let infuse for at least 3 hours before serving.