Preheat your oven to 425°F (220°C) and place a medium-sized metal roasting tin inside to heat up.

In a large mixing bowl, whisk together the flour, eggs, and half of the milk until you have a smooth, thick paste.

Gradually whisk in the remaining milk, thyme, rosemary, salt, and pepper until the batter is the consistency of heavy cream, then let it rest for 10 minutes.

Carefully remove the hot roasting tin from the oven, add the vegetable oil or beef dripping, and place the sausages inside, rolling them to coat.

Return the tin to the oven and bake for 10-12 minutes until the sausages are lightly browned and the fat is smoking hot.

Quickly pour the resting batter into the hot tin around the sausages, working fast to maintain the oven's heat.

Bake for 25-30 minutes without opening the oven door, until the batter has puffed up significantly and turned a deep golden brown.

While the dish bakes, sauté the sliced red onions in butter over medium heat until soft and caramelized, then add the beef stock and simmer until reduced to a rich gravy.

Remove the Toad in the Hole from the oven and serve immediately, smothered in the hot onion gravy.