Separate the turkey into eight piles on a plate, and top evenly with cheese so you can quickly top each crepe as it cooks in the pan. Black Forest turkey has a subtle smoked flavor. You can also use oven-roasted turkey.
Preheat oven to 300°.
Combine milk, 2 teaspoons oil, butter, and eggs in a blender; blend until smooth. Weigh or lightly spoon flour into a dry measuring cup; level with a knife. Add flour, baking powder, sugar, and salt to blender; blend until smooth. Place batter in a bowl; cover with plastic wrap. Refrigerate 10 minutes.
Heat an 8-inch nonstick skillet or crepe pan over medium heat. Brush 1/4 teaspoon oil over pan. Add 2 tablespoons batter to pan, tilting pan until batter is in an even layer. Cook 30 to 45 seconds or until edges begin to brown. Top half of crepe with 1/2 ounce turkey, about 4 teaspoons cheese, and 1/2 teaspoon Dijon mustard. Fold crepe over filling; fold in half again to form a triangle. Gently remove crepe from pan, and place on a baking sheet; keep warm in oven. Repeat procedure with remaining oil, batter, turkey, cheese, and Dijon mustard to yield 8 filled crepes.