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21 Day Aged Sirloin Steak in Black Garlic Butter

21 Day Aged Sirloin Steak in Black Garlic Butter

with Spring Onion Mash and Mustard Dressed Baby Leaf Salad
Recipe Development Team
Recipe Development TeamUpdated on June 24, 2026
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Calories
897 kcal
Protein
48.1g protein
Total
30 minutes
Difficulty
Medium
Allergens:
  • Milk
  • Sulphites
  • Mustard
Produced in a facility that processes eggs, milk, fish, peanuts, sesame, shellfish, soy, tree nuts, and wheat.
serving amount

2 unit(s)

21 Day Aged British Sirloin Steaks

30 grams

Unsalted Butter

(Contains: Milk)

450 grams

Potatoes

125 grams

Baby Plum Tomatoes

1 unit(s)

Spring Onion

1 bunch(es)

Flat Leaf Parsley

20 grams

Black Garlic Paste

10 grams

Dijon Mustard

(Contains: Sulphites, Mustard)

12 milliliter(s)

Red Wine Vinegar

(Contains: Sulphites)

50 grams

Baby Leaf Mix

50 grams

Greek Style Salad Cheese

(Contains: Milk)

1 sachet(s)

Chilli Flakes

Not included in your delivery

2 tbsp

Olive Oil for the Dressing

Energy (kJ)3751 kJ
Energy (kcal)897 kcal
Fat51.5 g
of which saturates23.6 g
Carbohydrate48.8 g
of which sugars5.3 g
Dietary Fibre6.3 g
Protein48.1 g
Salt1.7 g
Potassium1080.3 mg
Calcium32.6 mg
Iron1.4 mg
Due to the different suppliers we purchase our products from, nutritional facts per meal can vary from the website to what is received in the delivered box, depending on your region.
Large Saucepan
Small Bowl
Medium Bowl
Aluminum Foil
Colander

Cooking Steps

Start the Mash
1

Bring a large saucepan of water with ½ tsp salt to the boil for the potatoes.

Remove the steaks and butter from your fridge to allow them to come up to room temperature.

Chop the potatoes into 2cm chunks (peel first if you prefer).

When your pan of water is boiling, add the potatoes and cook until you can easily slip a knife through, 15-20 mins.

Prep Time
2

Meanwhile, halve the baby plum tomatoes.

Trim and thinly slice the spring onion

Finely chop the parsley (stalks and all).

Add the parsley and black garlic paste into a small bowl with the butter and mash with a fork until combined. Season with salt and a pinch of chilli flakes (add less if you'd prefer things milder), then set the herby black garlic butter aside.

Mix the Salad Dressing
3

In a medium bowl, combine the Dijon mustard and red wine vinegar, then gradually mix in the olive oil for the dressing (see pantry for amount) with a fork or whisk until well combined.

Season with salt and pepper, then set the salad dressing aside for now.

Cook your Steaks
4

Heat a drizzle of oil in a large frying pan on high heat. Season the steaks with salt and pepper.

Once hot, lay the steaks into the pan and fry until browned, 1 min on each side.

Lower the heat slightly and cook for another 1-2 mins on each side if you want them medium-rare. TIP: Cook for 1-2 mins more if you like it more well done. 

Mash the Potatoes
5

Once cooked, transfer the steaks to a plate and spoon over the herby black garlic butter. Cover loosely with foil and allow to rest for a couple of mins. IMPORTANT: Wash your hands and equipment after handling raw meat. The steak is safe to eat when browned on the outside.

While the steaks rest, drain the cooked potatoes in a colander and return to the pan, off the heat.

Add a knob of butter and a splash of milk (if you have any) and mash until smooth. Season with salt and pepper, then stir through the spring onion.

Finish and Serve
6

When ready to serve, slice the steaks widthways into 1cm thick slices.

Share the mash between your plates, then plate up the steak alongside, spooning over the herby black garlic butter.

Toss the baby leaves and tomatoes in the mustard dressing and add to your plates. Crumble over the Greek style salad cheese

Sprinkle with the remaining chilli flakes to finish.

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