Combine mayonnaise and mustard.
Spread over one side of each slice of bread.
Place turkey on top of 4 slices.
Top with bread.
Place lettuce leaves, tomato slices and hard-cooked egg slices on top; season to taste with salt and pepper.
Top with basil leaves.
Cover with remaining slices of bread.
Cut each sandwich into 4 wedges.
Wrap with plastic film and refrigerate.