Place the potatoes and 1 teaspoon of the salt in a pot and cover with cold water. Bring to a boil, then lower the heat to medium and cook until the potatoes are fork-tender, 20 to 25 minutes. Drain the potatoes, then return them to the pot. Add the lemon juice and ½ teaspoon of black pepper and use a potato masher to mash them. Set aside.

In a large bowl, whisk together the eggs, parsley, green onions, flour, remaining ½ teaspoon salt and remaining ½ teaspoon black pepper until well combined.

Heat 1 teaspoon olive oil in a 6-inch nonstick skillet over medium heat. Measure out ½ cup of the omelet mixture and pour it into the heated skillet. Cook until the eggs are set and golden brown on the bottom, about 2 minutes, then flip and cook the other side for an additional 1 minute.

Transfer the omelet to a cooling rack. Continue with the remaining oil and batter, making 8 omelets.

Divide the mashed potatoes between the 8 omelets (about ½ cup in each), placing it in the middle of each. Roll up the omelets to enclose the potatoes and stack them on a plate to serve. Enjoy immediately.