Preheat your oven to 375°F.

Heat olive oil in a large sauté pan over medium. Add the leeks and sauté for 3-4 minutes, until they've started to soften. Add the mushrooms, salt and pepper and cook another 10 minutes, or until all of the mushrooms have just cooked through.

Add the garlic and stir through, then add the Swiss chard and cook until just wilted. Add the chard in batches if it doesn't all fit at once.

Put the farfel into a large mixing bowl and pour the cooked vegetables over. Add the chicken stock, stir through and set aside for 5 minutes, or until all of the stock has been absorbed.

Spray a 2-quart baking dish with oil then spoon the stuffing mixture in. Bake for 45 minutes or until the edges are golden brown.