Cut the potatoes (peeled) into small bite-sized pieces that are a 1/4 inch (0.625 cm) thick, and roughly chop the onion

Heat a 10-inch (25 cm) nonstick fry pan with a medium heat and add in 1/3 cup (90 ml) olive oil

After a couple of minutes, add in the chopped onion and mix together, after 3 to 4 minutes, add in the sliced potatoes and mix together, then mix every 2 to 3 minutes so all the potatoes evenly fry

In the meantime, crack the eggs into a large bowl, season with salt & pepper, and whisk together

After frying the potatoes for 20 to 25 minutes and they're lightly golden fried and cooked through, season with salt & pepper, mix together, then remove from the heat and transfer the mixture into the bowl with the whisked eggs, making sure to reserve the olive oil in the pan, mix the mixture together and let it sit for a couple of minutes

In the meantime, heat the same fry pan with a low-medium heat

After a couple of minutes, add in the potato and egg mixture, making sure it's all in a flat layer, and cook for 3 to 4 minutes without mixing

After 3 to 4 minutes it's time to flip the omelet, using a plate that is slightly smaller than the pan, place it over the omelet, and in one swift move, flip the pan into the plate, then slide the omelet back into the pan and compact it from the outer edges toward the center, cook for another 3 to 4 minutes or until the eggs are just cooked through, then transfer the omelet into a dish and cut into 8 wedges

To make the aioli, add the mayonnaise into a bowl, along with the grated garlic, lemon juice, and olive oil, then season with salt & pepper and whisk together

Cut the baguette into 6-inch (15 cm) pieces, and then cut each one in half lengthwise

Spread the garlic mayo aioli on both sides of the sandwich, then add a couple of wedges of the potato omelet, and top off with chopped chives, enjoy!