Firstly, make the batter by simply whisking all the Ingredients together until smooth. Season with a little salt and milled pepper and set aside until needed.
Tip the sausages into a medium sized roasting tin drizzle with 1tbsp of olive oil, cook in the oven for about 5 minutes then add the mushrooms and continue cooking for a further 3-4 minutes.
Scatter over the sweetcorn and peas then pour in the batter. Pop straight into the oven and cook for about 30 minutes until well risen and golden in colour.