Crack eggs into a bowl with flour and mix together until smooth.
Pour in the milk, rosemary, salt and pepper and mix until combined, put in the fridge for 15mins.
Add oil into a oven dish ( we use a 25cm cake tin ) and put in a preheated oven at 200 to warm up.
Cook sausages in a frying pan with a little oil.
After the oil in the oven tray is nice and hot add in the batter and cooked sausages. You want it to sizzle when the batter is added. Put back into the oven for 25mins.
For the gravy, fry finly sliced onions in a frying pan for 5mins until soft and slightly charred, add a spoon of flour and mix around for a 1min, coating all the onions evenly. After the flour is cooked out add in a jug of beef stock, stir together and leave simmering on the side for 15mins until reduced down.
For the mash potato, chop potatoes into halfs and skin them. Boil until soft, go softer than regular boiled spuds. Drain and put back into the pan and mash. I find doing this before adding butter and milk removes most of the lumps. When all mashed well add a spoon of butter and mash and combine, if milk is needed after this to make it more wet add a splash and again combine. Set aside on a very very low heat with the lid on to stay warm.