Heat the olive oil in a large skillet over medium heat. Add the spinach, sprinkle with salt and pepper. Cook for about 1 minute, using tongs to turn the spinach until it wilts. Transfer the spinach to a plate. Carefully wipe out the skillet for later in the recipe.
Lay 2slices of bread on a plate. Arrange the spinach evenly on the 2slices of bread. Using ateaspoon, dollop the ricotta cheese evenly over the spinach. Arrange 12 of the grape tomato halves over the spinach. Scatter the mozzarella over the top. Top with the other 2slices of bread. Lightly press the sandwich together using your hand.
Crack the eggs into a shallow bowl. Add the water and whisk to blend. Season with salt and pepper. Dip the sandwiches into the eggs to coat evenly.
Melt the butter in the skillet over low-medium heat. Arrange the sandwiches in the skillet and cook for 2-3 minutes, until the egg on the underside is cooked and golden brown, then using two spatulas, carefully turn the sandwich to cook the other side for about 2 minutes until the egg is cooked and golden brown. Transfer to a clean plate. Cut each sandwich in half on the diagonal. Dust with powdered sugar and serve with raspberry preserves for dipping.