Line a cookie sheet or jellyroll pan with a cooling rack; set aside. Preheat the oven to 200°F.

Whisk the egg and water together in a mixing bowl. Add flour, salt, and baking powder and whisk thoroughly for 2 to 3 minutes or until smooth, scraping sides of the bowl.

On one slice of bread, arrange one slice of cheese, two slices of ham, two slices of turkey, and one slice of cheese, covering the bread evenly. Place another piece of bread on top and slice each sandwich in half diagonally.

Heat the oil to between 365°F and 375°F in a 10-inch pan. Dip half of the sandwich into the batter, allowing excess to drain, and very carefully place into the oil.

Repeat with the other sandwich half. Cook 3 minutes on each side, or until golden brown. Place the cooked sandwich on the prepared cookie sheet in a warm oven until ready to serve. Repeat with the other three sandwiches.

Cook one at a time, and allow the oil to reach the desired temperature between each sandwich.

Sprinkle with confectioner’s sugar and serve with blackberry preserves on the side.