Cook bacon over a medium high heat in a wide saucepan until rendered and crisp. Drain off some of the fat. Add shallots and apple. Cook until slightly caramelized. Add mussels and stir to coat. Deglaze with white wine, apple cider, and vinegar. Reduce slightly. Add cream, thyme, salt, and pepper. Cover and cook until all the mussels are open and the sauce is reduced and slightly thickened. Serve in the pan or transfer to a large, wide bowl. Serve with toasted country bread.