Begin by placing strong plain flour, a pinch of salt, eggs, and olive oil into a food processor. Blend until the mixture forms a consistent dough, which may take about 1–2 minutes. Once combined, wrap the dough in cling film and refrigerate for at least 1 hour to allow it to rest.

After resting, dust your countertop with flour and roll out the dough using a pasta machine, aiming for thin sheets. Cut these sheets into rectangles or squares that will fit your lasagne dish. Bring a pot of salted water to a boil and briefly blanch the pasta sheets for 30 seconds, then remove and cool on a kitchen towel.

In a chilled food processor, blend the fresh scallops until smooth, incorporating half of the double cream while seasoning with salt and pepper. Once the mixture is creamy and well combined, gently fold in the white crab meat until just mixed.

Start assembling your lasagne by placing a sheet of pasta at the bottom of your chosen dish or metal rings. Alternately layer the sheets with the crab mousse, repeating until all ingredients are formed into layers, finishing with a pasta sheet on top. Refrigerate these assembled lasagnes for at least 30 minutes to firm up.

In a saucepan over medium heat, sauté finely chopped shallots in a generous knob of unsalted butter until translucent. Next, deglaze the pan by adding white wine and wine vinegar, allowing the mixture to reduce by half. Gradually whisk in chicken stock and the remaining double cream, then remove from heat and gently blend in chilled diced butter for a smooth, emulsified sauce.

Fill your steamer with water and bring it to a gentle simmer. Place the assembled crab lasagnes in the steamer basket and cover. Steam for approximately 12 minutes, or until the pasta is tender and the mousse is heated through.

Once removed from the steamer, carefully slide a sharp knife around the edges of the rings to release the lasagne. Plate each portion, drizzle the rich beurre nantais sauce over the top, and garnish with freshly chopped chives and chervil.