Cheesy Shepherds/Cottage Pie

2 x Medium sized white onion sliced and chopped 
800g steak mince 
 Tablespoon cooking oil 
 5 level tablespoons of tomato ketchup 
 6 tablespoons of beef stock 
 Mixed Herbs 
 1.2kg potatoes 
 400g grated cheese 
 6 to 8 tablespoons of milk   
 Peel and chop the potatoes roughly in halves and place in saucepan. I usually boil a kettle of cold water and empty it into the saucepan of potatoes to speed up things and cook on high heat Grate the block of Cheese. Add cooking oil to frying pan and fry the steak mince and until starts to brown. Add chopped onions and sauté over medium heat until cooked but not browned. Keep an eye on the potatoes until they soften and fork goes through them with ease. Turn off heat drain off excess water in saucepan and steam (make sure not to burn) then mash. Add in grated cheese and milk and mix. Mix the mince, tomato ketchup, beef stock and a good dash of mixed herbs. Place this mixture into a casserole dish and spread evenly. Spread the mash mix over the top and spread evenly. Topping with extra grated cheese if you like your cheese! Place in a pre-heated oven at 190 degrees C for 30 mins. Remove, cut into slices and serve!