Place 12 large eggs in a pot, cover with cold water, and bring to a boil; once boiling, cover and remove from heat, then let stand 12 minutes. You should see the water come to a full boil before removing the pot.

Chill the boiled eggs in an ice bath for 10 minutes, then peel and halve lengthwise. The whites should feel cold and firm when ready to handle.

Cook the finely diced pancetta or guanciale in a cast iron skillet for 6-8 minutes until crispy, then drain and reserve 1 teaspoon of the fat. Look for deep golden-brown bits and a clear sizzle.

Mash the yolks with mayonnaise, Pecorino Romano, Dijon mustard, grated garlic, coarsely cracked black pepper, and the reserved pancetta fat until smooth. The mixture should be thick, cohesive, and glossy with no large lumps.

Pipe the filling into the egg white halves, creating a neat mound in each well. The filling should hold its shape when piped.

Top with crispy pancetta, shaved Pecorino Romano, cracked pepper, and fresh parsley for garnish. Finish with a visible peppery speckle on top and a few parsley leaves for contrast.