1 tablespoon olive oil 1 ½ cups diced yellow onion (about 1 medium onion) 1 garlic clove, minced 2 tablespoons heavy cream, plus more for brushing 3 tablespoons dried oregano 1 tablespoon finely chopped basil 1 tablespoon finely chopped Italian parsley 2 teaspoons smoked paprika 2 teaspoons kosher salt 1 teaspoon fennel seeds, toasted, crushed with mortar and pestle ¼ teaspoon red pepper flakes 2 teaspoons ground black pepper 1 pound ground pork (20% fat; do not use lean pork) 2 tablespoons unsalted butter, softened 1 teaspoon Dijon mustard Flour, for dusting 2 (9 ½-inch square) sheets all-butter puff pastry 2 teaspoons sesame seeds (preferably a mixture of black and white) Ketchup or Tomato Sauce (see recipe), for serving