- In a saucepan, cook the sweet potatoes (whole) in boiling water until tender. Drain, peel and finely mash with the sour cream. Season with salt and pepper.
- Preheat the oven’s broiler.
- In a saucepan, melt the butter. Add the flour and cook for 1 minute, stirring over medium heat. Whisk in the milk. Add the fennel seeds, white wine and chives. Stir until it thickens. Season with salt and pepper.
- With a pastry bag with a fluted tip, pipe the purée around the shells. Place four scallops in each shell.
- Drizzle on the sauce. Sprinkle with breadcrumbs and cheese. Bake in the middle of the oven for 5 to 8 minutes. If necessary, place the shells immediately below the heating element to brown slightly.
The shells can be prepared in advance and refrigerated. You will cook them at the last moment.