Peel and dice the onion.
Peel the carrots and the potatoes. Cut in 1cm-large pieces*.
Heat a large pot with olive oil. When hot, add then onion and sauté until translucent.
Add the carrots and caramelize over medium-high for 5 minutes. Add the potatoes and let cook for 5 minutes. Stir regularly and make sure the vegetables don't stick to the pot.
Deglaze with white wine. Simmer 3 minutes over medium-high heat. The wine should completely evaporate.
Add the water. Cover with a lid and reduce to medium heat. Let cook 25 minutes with the lid on. Remove the lid and cook 10 more minutes.
Season with salt and roughly mash with a potato masher.