In a deep fryer or large heavy-bottomed pot, heat 3 to 4 inches of oil to 325°F to 350°F. The oil should be hot but not smoking, and it should be deep enough to fully submerge a triple-decker sandwich.

Each sandwich will use 3 slices of bread. On one slice of bread, place a slice of turkey and a slice of Swiss cheese. On another slice of bread, place a slice of ham and a slice of American cheese. Place the third slice of bread in between and secure the corners of the triple-decker sandwich with toothpicks. Repeat for the remaining 2 sandwiches.

Combine the egg and water in a mixing bowl and beat well. Add the salt, sugar, flour, and baking powder and beat until smooth.

Quickly dip a sandwich into the batter, ensuring that all sides and surfaces are covered. The bread should be fully saturated but not falling apart.

Carefully lower the sandwich into the hot oil and fry until golden. If the oil is the right temperature, you should hear a gentle sizzle when the sandwich hits the oil. When the sandwich turns a warm golden color, remove it from the oil and place it on a paper towel to drain. Repeat for the remaining sandwiches.

After the sandwiches have cooled for a few minutes, remove the toothpicks. Slice the sandwiches into fourths (triangles) and sprinkle with powdered sugar.

Serve with raspberry preserves, as well as pickle slices and French fries if desired.