Beef steak with duchesse potatoes, Béarnaise sauce, onion rings served on a plank

With a plank steak you can do many variations. Here you have a yummy béarnaise sauce recipe, but you can also make a cold crème fraiche based dressing if you want. You can also mix pork tenderloin medallions with the beef tenderloin for a different version of this recipe.
Duchesse potatoes
Béarnaise sauce
Onion rings
Green beans

Ingredients 4 servings

Duchesse potatoes
800 g (28.22 oz) potatoes
50 g (1.76 oz) butter
10 g (0.35 oz) chives
10 g (0.35 oz) parsley

800 g (28.22 oz) beef tenderloin
2 g (0.07 oz) salt
1 g (0.04 oz) black pepper
20 g (0.71 oz) butter

Béarnaise sauce
80 g (2.82 oz) egg yolks
40 ml (1.35 fl oz) water
20 ml (0.68 fl oz) white wine vinegar
250 g (8.82 oz) butter
10 g (0.35 oz) fresh tarragon
2 g (0.07 oz) salt

Onion rings
500 ml (16.91 fl oz) neutral vegetable oil
200 ml (6.76 fl oz) beer
100 g (3.53 oz) flour
400 g (14.11 oz) onions


Duchesse potatoes
Boil the potatoes until they are soft.
Strain the liquid off the potatoes and then add the butter while mashing the potatoes.
Chop the chives and parsley very fine and add to the mashed potatoes.
Transfer the potato mash to a piping bag with a star tip.

Cut the tenderloin into 4 pieces.
Salt and pepper the steaks.
Heat a frying pan to high heat. Add the butter and fry the steaks for 5 minutes on each side.
Transfer the steaks to a plate and tent it with tin foil.

Bearnaise sauce
Boil some water in a small pan. Put a heat proof bowl over the pan to create a water bath.
Melt the butter in a pot.
Chop the tarragon very fine and add to the butter.
Keep the butter warm while preparing the eggs.
Add the egg yolks, water and white wine vinegar to the bowl and stir. Cook over the water bath, while stirring, until the mixture reaches 72° C (161.6 degrees Fahrenheit). If the egg yolk starts to curdle before reaching that temperature, just add some cold water and continue whisking.
Take the bowl off the heat and whisk in the melted tarragon butter, a little by little. Add Salt to taste.

Onion rings
Heat the vegetable oil to 175° C (347 degrees Fahrenheit).
Carefully whisk the flour and beer together. Try to keep some of the bubbles by not over whisking.
Cut the onions and separate them to get rings.
Dip the onion rings into the beer batter and then into the oil.
Deep fry the onion rings until they are golden brown.
Let the onion rings sit on a wire rack or kitchen paper towels.

Preheat an oven to 200° C (392 degrees Fahrenheit).
Pipe the potato around the plank and place it in the oven until the potatoes are golden brown.
Fry the green beans in some butter and salt.
Arrange the beef, green beans, onion rings and sauce on the plate.