To make the butter sauce, slice the shallot finely, add the tarragon and peppercorns, in a pan add the vinegar and wine to the shallots and reduce by half, slowly add the diced chilled butter and whisk until melted, season, pass and set aside.
In a non-stick pan roast the sweetbread in small nuggets until golden brown, add the thinly sliced pancetta lardons and cook until both are crispy, drain and set aside.
In a non-stick pan roast the halibut skin side down until golden brown, flip over and finish cooking until fish is translucent, depends on thickness of fish for cooking times.
Slice the smoked oysters and add to the beurre blanc, warm gently. In a separate pan warm the cooked peas in a little butter emulsion and then add the sweetbreads and pancetta.
To plate, place the peas in the centre of your plate, add the chopped chives to the sauce and then sauce around the peas making sure of plenty of oyster per plate, top the peas with the halibut and finish with the pea shoots and tendrils.