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21 Day Aged Sirloin Steak

21 Day Aged Sirloin Steak

with Mustard Crushed Potatoes, Spinach and Sun-Dried Tomato Butter
4.5(155)
Recipe Development Team
Recipe Development TeamUpdated on February 10, 2026
Calories
602 kcal
Protein
44g protein
Difficulty
Medium
Produced in a facility that processes eggs, milk, fish, peanuts, sesame, shellfish, soy, tree nuts, and wheat.
serving amount

350

Salad Potatoes

1

Wholegrain Mustard

2

21 Day Aged British Sirloin Steaks

30

Sundried Tomatoes

½

Flat Leaf Parsley

30

Unsalted Butter

125

Baby Spinach

Energy (kcal)602 kcal
Energy (kJ)2519 kJ
Fat32 g
of which saturates16 g
Carbohydrate35 g
of which sugars8 g
Protein44 g
Salt2 g
Always refer to the product label for the most accurate ingredient and allergen information.

Instructions

Get Started
1

Remove the steaks and butter from the fridge to bring them up to room temperature. Submerge the sun-dried tomatoes in a bowl of hot water and set aside. Bring a large saucepan of water with a pinch of salt to the boil for the potatoes.

2

Chop the new potatoes into 2cm chunks (no need to peel). Add the potatoes to the pan of boiling water and cook until you can easily slip a knife through, 12-15 mins. Drain in a colander and set aside when cooked.

Make the Butter
3

Put the butter in a small bowl and mash with a fork until soft. Remove the sun-dried tomatoes from the water, pat dry with some kitchen paper and finely chop. Finely chop the parsley (stalks and all). Stir the sun-dried tomatoes and half the parsley through the butter. Set aside.

4

Put a frying pan on high heat with a drizzle of oil. Season the steaks with salt and pepper. When the oil is hot, lay the steaks in the pan and brown for a 1 minute on each side. Once browned, lower the heat slightly and cook for another 1-2 mins on each side. tTIP: This will cook the steak to medium rare - if you like yours less rare just cook for 1-2 mins more. IMPORTANT: The steak is safe to eat when the outside is cooked. Transfer to a plate, top with the tomato butter and leave to rest.

5

While the steak rests, return the now empty frying pan to high heat with a drizzle of oil. When hot, tip in the drained potatoes and lower the heat to medium. Leave to cook, turning occasionally, until browned at the edges, 3-4 mins. Use a fork to gently crush a few of the potatoes - this will give you lots of delicious crispy edges!

Serve
6

Stir the wholegrain mustard through the potatoes followed by the spinach. Lower the heat and leave for 1 minute to wilt the spinach while you slice the steak. Slice the steak and serve with the mustard smashed potatoes alongside. Spoon over the sun-dried tomato butter (it should have melted while the steaks rest!) and finish with a sprinkling of remaining parsley. Enjoy!

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