Preheat oven to fan 180°C/conventional 200°C/Gas mark 6. Put a generous half-teaspoonful of sunflower oil in the bottom of each cup of a deep 12-hole mini muffin pan set on a baking tray.
Pour the milk into a jug, add the egg, flour and a pinch of salt and whisk everything together with a hand blender or wire whisk until a smooth batter forms. Put the muffin pan in the oven for a minute or so until the oil is very hot.
Carefully remove from the oven and quickly fill the cups just under two-thirds full (this may not seem enough batter, but they puff up in the oven).
Drop a speedy sausage into each cup and bake for 20-25 minutes until golden brown, well risen and crisp. Serve with buttery mashed potatoes and veg.