To make the cranberry sauce, bring cranberries, sugar and 1 cup water to a boil in a saucepan over high heat. Reduce the heat to medium and cook until the berries pop and the sauce thickens, about 10 minutes. Cool.
Preheat the oven to 375°F. Arrange the bacon on a slotted broiler pan in a single layer and bake until crispy, about 25 minutes. Transfer to paper towels to drain.
Meanwhile, in a medium bowl, combine the turkey, parsley, onion, poultry seasoning and celery seed; season with salt and pepper. Form the mixture into 4 patties that are thinner in the center for even cooking.
In a large, nonstick skillet, heat the oil, two turns of the pan, over medium-high. Add the patties and cook, turning once, to desired doneness, about 12 minutes for medium. Arrange the buttered toast on plates and top with the burgers.
In the same skillet the burgers were cooked in, melt the butter. When it foams, whisk in the flour and some coarsely ground black pepper. Add the stock and Worcestershire, and whisk until the gravy thickens, about 4 minutes. Pour the gravy over the burgers.
Chop the bacon. Top the burgers with the bacon and scallions. Serve with the cranberry sauce.