Boil the potatoes in salted water for 8-10 minutes until tender.
Drain potatoes, crush with a fork, add butter, and season with salt and pepper.
Heat 110g of butter in a frying pan until it turns nut-brown.
Stir in lemon juice, salt, and pepper, then remove from heat.
Season sea bass and lemon sole fillets with salt.
Sear sea bass skin-side down in olive oil for one minute.
Lower heat and cook the sea bass skin-side down for 4-5 minutes.
Flip the sea bass, add extra butter to the pan, and baste before resting.
Fry the lemon sole in oil and butter for two minutes on one side and one minute on the other.
Plate the crushed potatoes with sea bass and lemon sole, then spoon over the brown butter sauce.
Garnish with watercress and muslin-wrapped lemons.