Thaw pastry for 30 minutes. Preheat the oven to 400° . Thaw spinach. Squeeze by handfuls to remove excess water. Combine spinach, cheese, leek, and garlic in a bowl and set aside. Unfold pastry onto a flat surface and brush with soy milk. Top entire surface with spinach mixture and, beginning on a long side, roll up jelly-roll style. Cut crosswise onto 18 slices. Brush with soy milk and place on parchment-lined cookie sheet. Bake for 15 minutes or until golden brown.