In a large saucepan, combine the wine with the shallot, lemon, thyme sprigs and peppercorns and bring to a boil. Add the mussels, cover and cook over high heat, stirring occasionally, until the mussels open, about 5 minutes. Remove from the heat and discard any mussels that don't open. Pull the mussels out of their shells and discard half of each shell. Arrange the remaining shells on a baking sheet in 1 layer and place a mussel in each shell. Strain the broth into a glass measuring cup, leaving any grit behind.