Pour the stock into a medium saucepan, and add the dried mushrooms.
50 g dried mushrooms, 1300 ml vegetable stock
Bring to a simmer and let the mushrooms steep in it, squishing them around so they let out all their delicious mushroomy essence. Keep them in the stock until later when you'll need them.
In a big saucepan, warm the olive oil gently, then add the onions & garlic cook until translucent.