Meanwhile, in a small pot, bring the wine, vinegar, shallots, tarragon sprig and crushed pepper to a boil. Let reduce until only about 3 tbsp (45 ml) of liquid remains, about 5 minutes. Strain through a sieve placed over a bowl. Compost the residue.
Place the bowl over a pot of simmering water. Whisk the egg yolks into the vinegar reduction until the sauce is thick and foamy.
Remove the bowl from the pot of water. Off the heat, slowly whisk in the melted butter. Add the chopped tarragon. Adjust the seasoning. If the sauce is too thick, whisk in a little hot water. Cover with plastic wrap. Keep warm. When ready to serve, pour the sauce into a gravy boat.
Cod
Place the cod pieces on the second baking sheet and brush with the oil on both sides. Season with salt and pepper. Bake on the upper rack of the oven for 10 minutes or until cooked through.
To reheat the green beans, place the bundles on the baking sheet with the potatoes and bake for 5 minutes, turning them over halfway through cooking.
On a large, warm serving dish, place the potatoes and bean bundles. Top with the fish. Serve immediately with the Béarnaise sauce.
Note from Ricardo
To save some time, you can prepare a few elements of this dish in advance, such as boiling the potatoes and green beans, and assembling the beans into bundles with the ham. For the Béarnaise sauce, you can prepare the wine reduction, separate the egg yolks and melt the butter in advance. If you have enough space in your refrigerator, you can arrange the raw cod on one of the baking sheets.
