Start by gathering all your ingredients. Draining the tuna thoroughly is crucial; you don’t want excess moisture in your mixture. Finely chop the red onion and parsley. Prepare a large bowl for mixing.

In the mixing bowl, add the drained tuna, eggs, chopped onions, and parsley. Stir everything until well combined. This is where the excitement starts as you see the colors and textures come together!

Next, sprinkle in the Italian breadcrumbs, Parmesan cheese, Dijon mustard, lemon juice, and black pepper. Slowly fold these ingredients into the tuna mixture. Be gentle, but ensure everything is evenly distributed—you want every bite to have flavor.

With your hands, scoop out small portions of the mixture and shape them into flat, round patties. Aim for about half an inch thick; this thickness allows for a delightful crispiness while ensuring they cook through.

In a large skillet, heat the olive oil over medium heat. You want the oil hot enough to sizzle when the patties touch it. This step is key to achieving that crispy exterior that makes every bite enjoyable.

Place the formed patties carefully into the skillet. Cook for about 4-5 minutes on each side, or until they are golden brown. Resist the urge to flip them too soon—the golden crust is what you're aiming for!

Once cooked, transfer the patties to a plate lined with paper towels to absorb any excess oil. Serve them warm and enjoy the deliciousness!