Fennel, Cauliflower & Truffle Soup with Gruyere Croutons

Ingredients

• 1/4 cup olive oil
• 1 large fennel bulb (approx. 900g), cut into 2cm chunks & reserve fronds for later
• 1 cauliflower (approx. 900g), cut into small florets
• 4 cloves garlic, unpeeled
• 2 leeks washed & finely sliced
• 1 L chicken stock
• 2 large potatoes (approx. 450g), peeled & diced into 2cm cubes
• 125 ml sour cream
• 2 tsp garlic & truffle salt
• Freshly ground black pepper