Pour around 50 ml of olive oil into a frying pan over medium-low heat and cook the onion for 10–15 minutes until lovely and soft.
Once the onion is golden, add the garlic and diced asparagus and cook over high heat for 5-10 minutes until tender. Once cooked, remove from the heat and set aside.
In a large bowl, beat the eggs, then add the asparagus and onion mix and a few pinches of seasoning to taste.
In a large 25cm (8-inch) frying pan on high heat, Pour the remaining olive oil for the tortilla When the oil is hot, add the egg, onion, and asparagus mixture. Cook for around 3-4 minutes and reduce heat to low-medium heat.
Once the mixture starts to set around the edges, use a wooden spatula to press down the edges. The edges will begin to set much faster than the middle.
Cover the frying pan with a flat lid or large chopping board and turn the tortilla carefully onto it. Return the pan to the heat and gently transfer the flipped tortilla into the pan to cook the other side on low heat for another 5-8 minutes.
Once cooked, remove from the pan and slide onto a chopping board. The tortilla should still be slightly juicy in the middle when you cut into it.
Serve with a few slices of fresh bread.