Preheat the oven to 400 degrees. Butter the inside of a 2 1/2quart souffle dish. In a large saucepan, melt the butter, add the flour and whisk to form a smooth roux. Cook over medium heat, stirring constantly, for 2 to 3 minutes. Add the milk and whisk vigorously until the mixture is smooth and thick, then cook at a low boil, stirring constantly, for another 2 to 3 minutes.
Remove the mixture from the heat, add the chevre and stir until the cheese is melted and wellincorporated. Stir in the egg yolks and season generously with salt and pepper (the seasoning should be intense here to compensate for the later addition of the egg whites).
With an electric mixer or by hand with a whisk, whip the egg whites until they form soft peaks. Stir 1/4 of the egg whites into the cheese mixture to lighten it, then carefully fold in the remaining egg whites. Fill the prepared souffle mold; it should be about 3/4 full. Sprinkle the top of the souffle with the dried thyme. Bake in the preheated oven until risen, golden brown and just barely firm in the center, 40 to 45 minutes. Serve immediately.