Prep all ingredients per the instructions above.

Place the eggs in a pot and cover with water by about 1 inch. Bring to a boil over medium-high heat. Once boiling, cook for 8 minutes. Drain and cool under cold running water. Peel once cool enough to handle.

Chop the peeled eggs and transfer to a bowl. Add mayonnaise, Dijon mustard, salt, and black pepper. Mix until well combined.

Toast the sourdough bread until lightly crisp.

Layer the toasted bread with spinach, tomato slices, egg salad, and red onion. Close the sandwiches. Cut in half.

Combine sparkling water, lemon slices, and fresh mint. Stir gently to combine. Add ice cubes if desired.

Serve the sandwich with apple slices and cheese alongside mint lemon sparkling water.