• Preheat the oven to 400°F. Grease a baking dish.
• Add the sausages to the baking dish and bake for about 10 minutes.
• In the meantime, whisk together the cornflour, chives, eggs, and parmesan. Add the milk in two stages, whisking in-between. Season with salt and pepper.
• Pour the batter into the baking dish around the sausages and return to the oven. Bake for abut 25 minutes until golden, puffed, and beautiful.

For the onion gravy

• Melt the butter in a frying pan over medium heat and add the onions and rosemary. Fry for about 10 minutes until softened.
• In the meantime, whisk the red wine with the corn flour and mustard.
• Add the red wine mixture to the pan and cook, stirring, until the alcohol has burned off.
• Add the stock and cook for about 15-20 minutes, until glossy and thickened, stirring occasionally.
• Serve the toad-in-the-hole hot, with the onion gravy on the side.