Preheat your oven to 425°F (220°C) and place a roasting pan inside to heat.
Whisk together the flour, milk, and eggs in a bowl until smooth to create your batter.
Add the sunflower oil to the hot roasting pan in the oven and let it heat for a few minutes.
Carefully place the sausages into the pan and cook for about 10 minutes until they start browning.
Pour the batter over the sausages evenly and return the pan to the oven. Bake for about 25-30 minutes until the batter is puffed and golden brown.