For years I have tried to find a way to cook cheaper cuts of beef perfectly. Recently I volunteered to cook a large joint of cold beef for a buffet. I was reluctant to pay an arm and a leg for sirloin, or bankrupt myself with fillet; rib is delicious but very fatty; topside and silverside are not at all fatty but my usual slow-ish method of cooking those cuts has tended to produce tough, unappetising old meat. On the internet I found various suggestions and to my delight, by studying various gurus including Good Housekeeping and Hugh Fearnley Whittingstall, I hit the jackpot. Provided you don’t mind your beef quite rare, it seems that the secret of roasting topside is quick, not slow cooking. This produces a succulent, pink meat, easy to carve thinly, not too fatty, giving out delicious essences, and wonderful dripping too if your butcher ties in a snug coat of beef fat all the way around it. (Mind you, I have a good, if expensive butcher. I am going to try this recipe with a supermarket rolled topside soon.) And although a large joint is expensive, make it an occasional treat for family and friends and it will repay you.
So here it is. To serve hot, cook with the usual trimmings. To serve cold, wrap tightly in foil then cool and refrigerate.
Ingredients
2kg rolled topside of beef.
1 tbspn olive oil
1 tbspn dijon mustard
1 tbspn dark brown sugar
Fine sea salt
Freshly ground black pepper.
Method
Take the meat out of the fridge an hour before cooking and wipe it all dry with paper towels. Mix up the sugar, oil and mustard and spread it all over the joint. Season with salt and black pepper. Put the joint in a roasting tin- one which will accommodate it with space around the sides of the meat. Put it in a hot oven (200 deg fan, 220 non fan) for thirty minutes exactly. Then turn the oven down to 130 ( fan-150 non fan) and cook for ten minutes per 500g and no more.
Take out immediately, put on a plate and cover with foil. Rest it where it is (i.e. not in a warm oven) for about 45 minutes while you are finishing off the vegetables etc, then carve into thin slices. If you want it for a cold buffet or sandwiches, cool a little then wrap tightly in foil and refrigerate until needed. It will keep for few days in the fridge and moreover, you can freeze it if you like.
Microwave: no use here
Freezing: you can easily freeze this.
Read, Cook, Enjoy 
I usually cook my beef joints quickly (I love my beef rare) but tried brisket slow roasted recently, absolutely loved that. This looks lovely and pink!
I followed this recipe with a 3.5kg joint of topside, prepared by my butcher, and it was absolutely perfect. Thank you so much! I was frightened that the beef wasn’t cooked when the time was up, but I kept faith in the recipe and removed the joint from the oven. I had cooked it to be eaten cold as part of a buffet and my butcher very kindly offered to slice up the beef. He told me later that when I’d handed it to him he’d been concerned that it was under-cooked. We were both proved wrong! The colour of the meat was just the same as the beef in your photograph – evenly coral-pink all the way through, with a browned crust. The beef was beautifully tender and tasty. I should add that the topside was top-quality organic beef and had been hung for many days, which meant that no blood came running from the beef and the meat was not dry. Sixty people came to the buffet party and everyone was praising the rare beef! I’m so grateful to you for your recipe.
I also cook beef to HFW’s timings. However, if cooking a smaller piece I find I need to reduce the sizzle time by 10 mins to achieve the desired level of rareness.