Step 1

Preheat the oven to 200°C/400°F/Gas Mark Pour the oil into a 30 x 20cm roasting tin, brushing around the sides of the tin to grease. Add the sausages, squash and onions to the tin and cook for 15 minutes.

Step 2

Meanwhile, make a batter: Put the eggs, flour, mustard, salt and milk in a blender or food processor, and whizz together until smooth. (Alternatively, whisk together in a bowl.)

Step 3

Turn the sausages, squash and onions, then carefully pour in the Yorkshire batter. Cook for 30 minutes, until the batter is puffy, golden and shrinking away from the sides of the tin. Slice into wedges to serve.