Root Vegetable Casserole with Parsley Dump

Name: Root Vegetable Casserole with Parsley Dump
Ingredients: * 300g parsnip, cut lengthway into 4; * 4tbsp olive oil; * sea salt and freshly ground pepper, to taste; * for the casserole:; * 8 shallot,; * 3 garlic clove, thinly sliced; * 4 medium sized sweet potato,; * 350g swede,; * 200g chestnut mushroom, cleaned and; * 350ml vegetable stock; * 200ml cider; * 1 bay leaf; * 1 1/2 tsp cornflour; * for the dumpling:; * 125g self raising flour; * 3tbsp fresh parsley, chopped; * 60g dairy free margarine; * 3tbsp nutritional yeast (optional)