How to cook topside beef in an Aga cooker

Few Sunday roasts feel as celebratory as a perfectly pink topside beef joint, especially when it comes out of the Aga with crisp fat, caramelised vegetables, and just enough heat left to finish the Yorkshire puddings.

This guide breaks down every stage from bringing the meat to room temperature to turning leftovers into weekday suppers, so you can enjoy consistent results whether you run a classic oil Aga in Harrogate or an eControl conversion in York.

Topside Beef – The Basics

Topside comes from the inner thigh of the cow. It is lean, full of flavour, and benefits from fast, high roasting followed by a gentle rest. Because Aga cookers deliver constant radiant heat, they are ideal for cooking the exterior without drying out the joints. Before you start:

• Buy the right size joint: 1 kg feeds 4–5 people; 1.5 kg feeds 6–7.
• Ask your butcher to tie the joint so it holds shape and cooks evenly.
• Remove the beef from the fridge at least an hour before cooking.
• Pat the surface dry, massage with rapeseed oil, and season generously with sea salt, cracked pepper, and optional crushed garlic or rosemary.

Which Aga Oven Should I Use?

Whether you own a traditional two-oven model or a modern eControl, the hottest oven – the roasting oven – is your best friend. It holds roughly 240–260°C, similar to a conventional fan oven set to 220°C. Use the simmering oven as a holding zone once the beef has browned, or for resting and low-temperature cooking.

Topside Beef Cooking Times

Use the table below as a quick reference. All timings assume you start in the roasting oven on the second set of runners and finish with at least 30 minutes of resting on the simmering plate (lid down) or in the simmering oven with the door slightly ajar.

For a classic approach, hang the roasting tin from the third set of runners in the roasting oven for 12 minutes per 450 g (approximately 12 minutes per lb). If you prefer a slower finish, spend one third of the time in the roasting oven to brown, then move the joint to the simmering oven for the remaining two thirds.

Checking Internal Temperature

• Rare: 50–52°C
• Medium rare: 55°C
• Medium: 60°C
• Well done: 70°C+

Insert an instant-read thermometer into the thickest part after the first 20 minutes so you can adjust the cooking time if needed. Remember the meat will rise by 3–5°C while resting.

Step-By-Step: How to Cook Topside Beef in an Aga Cooker

1. Heat the roasting oven: Ensure the thermometer reads in the green band for at least 30 minutes.
2. Prep the roasting tin: Scatter chopped carrots, onions, celery, and a halved garlic bulb. These act as a trivet and caramelise into the base for gravy.
3. Sear in the roasting oven: Place the joint on the vegetables, fat side up, and slide the tin onto the second runners. Cook for 20 minutes to seal.
4. Adjust for doneness: Continue in the roasting oven for rare/medium results, or move to the simmering oven for gentler heat if you prefer very tender slices.
5. Baste halfway: Spoon rendered fat over the top after 30 minutes to keep the crust glossy.
6. Rest properly: Transfer the beef to a warm plate, tent with foil, and rest for at least 30 minutes. Use this time to make gravy on the simmering plate.
7. Slice across the grain: Hold the joint steady with a carving fork and cut thin slices so every portion stays tender.

How Long To Cook 1 kg Topside Beef?

The sweet spot for a 1 kg topside beef joint is 25–30 minutes in the roasting oven for medium-rare, followed by 30 minutes of resting. If you use the two-oven method (roasting then simmering), try 15 minutes in the roasting oven and 20 minutes in the simmering oven.

Best Way To Cook Topside Beef In An Aga

Many Aga cooks swear by the “start hot, finish slow” method. It gives you deep colour without overcooking. For a 1.5 kg joint:

• Roasting oven: 20 minutes uncovered.
• Simmering oven: 30 minutes loosely covered with foil.
• Rest: 30 minutes on the closed simmering plate.

This method is especially handy if you have electric conversions such as ElectricKit Advanced or eControl Series X Squared that allow precise timing and separate zone control. You can turn the roasting oven off once the beef moves downstairs, preserving energy.

How To Roast Topside Beef Trimmings

Crispy Roast Potatoes

Boil peeled Maris Piper potatoes for 8 minutes, let them steam dry, then shake them to rough up the edges. Heat beef dripping in a roasting tin directly on the floor of the roasting oven until smoking. Tip in the potatoes, season, and roast for 45–60 minutes, turning twice.

Yorkshire Puddings

Make the batter ahead (equal volumes of eggs, milk, and flour). Rest for at least 30 minutes. Pour a teaspoon of beef fat into each muffin cup, place on the floor of the roasting oven for 5 minutes, then add batter and bake for 18–20 minutes without opening the door.

Seasonal Vegetables

Steam tender-stem broccoli on the simmering plate and finish under the grill inside the roasting oven if you want charred edges. Honey-glazed carrots can be tucked into the simmering oven in a covered dish while the beef rests.

Making Proper Gravy

1. Skim most of the fat from the roasting tin, leaving two tablespoons behind.
2. Place the tin on the simmering plate, add a tablespoon of flour, and stir into the caramelised vegetables.
3. Deglaze with red wine or porter, scraping up fond.
4. Add beef stock, bay leaves, and a spoon of redcurrant jelly.
5. Simmer for 10 minutes, strain, and season.

Leftover Ideas

• Cold beef sandwiches: Slice thinly, pair with horseradish and rocket.
• Bubble and squeak: Fry leftover potatoes and greens on the hotplate with diced beef.
• Beef hash: Dice beef, mix with roasted vegetables, and crisp up in a cast-iron pan on the boiling plate.

Frequently Asked Questions

How long does 1 kg of topside beef take to cook?

Plan for 25–30 minutes in the Aga roasting oven and 30 minutes of resting for medium-rare. Add 5–10 minutes if you prefer medium.

Is topside beef tough?

Topside is lean, so it benefits from proper resting. Slicing thinly across the grain keeps each portion tender.

Can I cook topside beef overnight?

We recommend high-heat roasting for flavour. If you need a slow cook, move the joint to the simmering oven at 110–120°C and cook for 2–3 hours, but the texture will be more like pot roast.

How do I stop potatoes from sticking in the roasting tin?

Heat the fat until it shimmers before adding potatoes. Shake gently every 20 minutes and use a Bake-O-Glide liner if sticking persists.

What’s the best way to reheat leftover topside?

Layer slices in a lidded dish with a splash of gravy, cover, and warm in the simmering oven for 15 minutes.

Cook With Confidence

If you would like more advice on pairing your Aga with the ideal roasting setup, whether that is a reconditioned Aga or a modern electric conversion, get in touch with us. We can help you choose a Aga cooker, service your existing model, or install upgrades so every Sunday roast turns out exactly how you imagined.