In a pot on medium heat add the oil, and then the carrot and fresh mushrooms. When the carrot begins to soften and the mushrooms brown (about 10 minutes) add the flour to absorb the oily liquid at the bottom of the pot. Add a pinch of salt.
Add in the Porcini stock (dry mushroom rehydrating liquid) a ladle at a time. Stop when you are about 2 inches (5cm) from the top of the pot. Bring to a boil.
Add in the potato, pasta, onion, and rehydrated porcini mushrooms. Reduce to a simmer and put a lid on the pot. Let cook for 10 minutes, or until the potatoes and pasta are soft. Taste to adjust salt and pepper to your preference.
Take off the heat and ladle into bowls to serve. Garnish with chopped dill if you desire, or leave plain.
