Heat a large saucepan and add the olive oil and butter. Add carrots, and cook over medium high heat for about 15 minutes, or until slightly browned. If you burn them, order pizza.
Add the onions, lower the heat, and stir until onions are slightly yellowed. Add potatoes and the water they came in. Fill the rest of the pot with water until the vegetables are covered.
Cook for about 1 hour, until everything is happily mushy. Add water if necessary. Using an immersion blender, turn everything into a smooth, silky texture (add water if it's too thick). Add some salt and continue until well seasoned.
Add some of the herbs de provence, cook for a minute or so, and taste. Continue adding herbs de provence until the flavor is perfect.
Add water or salt as necessary to adjust seasoning. Serve garnished with parsley and sea salt.
