Preheat the oven to 200°C fan grill. Brush or spray each slice of the bread with a little olive oil. Lay on a baking tray and toast in the oven for 5 mins, until just beginning to brown. Remove from oven and use the whole garlic clove to rub over the toasted side. Turnover and return to the oven for a further 5 mins. Remove from oven once beginning to brown, and rub the garlic clove over the second toasted side.
Step 2
Sprinkle one side of the toasts with the cheese, then return to the oven to grill, allowing the cheese to melt. Set aside and keep warm while cooking the mushrooms.
Step 3
Heat a frying pan with the olive oil over a medium to low heat. Add the sliced onion and garlic and cook until the onion is tender, about 5 mins. Add the sliced mushrooms and fry for 8-10 mins until softened. Season to taste with ground nutmeg, salt and freshly ground black pepper. Add the parsley and mix well.
Step 4
Divide the mushrooms onto the top of each slice of prepared toasted bread. Sprinkle with toasted walnuts or pine nuts and plenty of extra parsley.
Tips
For a dairy free option, leave off the gruyere cheese or use dairy free cheese alternatives for a similar flavour.
Add 20g softened porcini mushrooms to the cooking mushrooms for extra intense mushroom flavour.