Dissolve 1 tablespoon of salt in enough water to cover the Brussels sprouts in a bowl, and soak the sprouts in the salty water for 1 hour. Drain off the water, and toss the sprouts in olive oil, sea salt, and black pepper to coat thoroughly.
Preheat oven to 475 degrees F (245 degrees C).
Place the bacon in a large, deep skillet, and cook over medium-high heat, stirring occasionally, until just beginning to brown at the edges, 5 to 8 minutes. Reduce heat to medium; stir in the shallot and mushrooms, then cook until the shallots turn translucent, about 5 more minutes. Sprinkle in the garlic, and cook 1 minute, then stir in the sherry and cream until well combined. Bring the mixture to a boil, and stir until reduced by half. The thickened sauce should coat the back of a spoon.
While the sauce is cooking, lay the Brussels sprouts, cut sides down, onto a baking sheet, and bake in the preheated oven until the sprouts are browned, about 15 minutes. Transfer the browned sprouts to the sauce, toss to coat, and season to taste with salt and black pepper.