For tigelle: Combine water, milk and yeast in a large bowl. Let stand, until yeast is foamy, about 5 minutes.

Add flour, oil and salt to wet ingredients and mix with a wooden spoon until a shaggy dough forms. Turn dough out onto a clean work surface. Knead until a smooth dough forms, about 5 minutes. Place dough in a lightly oiled bowl. Cover with plastic wrap or a damp towel and let rise in a warm place until doubled in size, about 1 hour.

Turn dough out onto a lightly floured work surface. Roll dough into a 1/4-inch thick rectangle. Using a 2-inch cookie cutter, cut dough into circles. Transfer dough rounds to a parchment paper lined baking sheet and cover with plastic wrap. Let rise until doubled in size, about 40 minutes.

Heat a large nonstick skillet over medium heat. Working in batches, cook dough rounds until light golden-brown and fully cooked, about 4 minutes per side. Repeat with remaining dough rounds.

For mortadella mousse: Combine mortadella, mascarpone, cheese and nutmeg in a food processor. Blend, scraping down the sides as needed, until a smooth mousse forms, about 1 minute. Transfer mousse to a piping bag fitted with a star tip. Pipe mousse on top of each tigelle. Garnish with additional Parmesan, pepper and basil. Serve and enjoy.