In a mixing bowl, combine chopped artichoke hearts, mayonnaise, and Dijon mustard. Add finely chopped shallot, celery, capers, parsley, lemon juice, salt, and pepper. Stir until all ingredients are fully integrated and creamy. Allow the filling to rest for about 15 minutes.

Preheat oven to 350°F (175°C). Place chosen bread on a baking sheet and lightly toast for about 7–10 minutes until crispy and golden.

Once the bread is toasted, spread the creamy artichoke filling over one slice. Layer with fresh lettuce or arugula and optional cheese. Top with another slice of bread.

Cut the assembled sandwich in half or quarters and serve immediately, ideally with a side salad or homemade chips.