Take the scallops out of the poaching water, and cut them in half (horizontally).
Pour the poaching water through a fine sieve, and keep this on the side.
Add the 50 grams of butter to a saucepan or baking pan and let this melt. Then add the flour and some shredded shallot and bake this until light brown. Thereafter you can add the poaching water again, and bring everything to a boil. Use whisk to mix everything and to ensure that the mixture is lump-free.
In the meanwhile, you can melt 20 grams of butter in another baking pan. Once the butter is melted and the pan is very hot, you can add the scallops. Bake these on a high heat for about 1 minute.
Dry the shells and preset those on your kitchen counter. When I serve these shells at home, I always make a standard of tin foil. By creating a globe and then a dimple on top. However, you could also place the shells on salt or a linnen napkin.
Mix the scallops, and the melting butter, with the ragout. Add the ragout to the shells and top off with fresh herbs/chives and dried seaweed. Serve directly.