1-Gathering and Preparing Ingredients: First, gather and prepare all ingredients as listed. Slice the ham thinly and have the bread and spreads ready for quick assembly. For dietary needs, prepare substitutes like vegan cheese or gluten-free bread ahead of time. Bringing ingredients to room temperature, such as the ham and Swiss cheese, ensures even heating.

2-Assembling the Sandwich: Spread mayonnaise on one side of one slice of bread and grainy mustard on one side of the other slice, laying them down with spreads facing up. Add a slice of Swiss cheese to each bread slice, then place the ham on top of the Swiss cheese on one slice before assembling the sandwich fully. This step creates the savory layers that make the sandwich so tasty.

3-Cooking the Sandwich: Beat the egg and half and half together in a small bowl until well combined. Heat a small skillet over medium heat and melt the butter, swirling to coat the pan. Quickly dip the sandwich in the egg mixture, coating both sides without soaking it too much, then place it in the skillet and cook until golden brown on one side about 3-4 minutes.

Flip the sandwich gently and cook the other side until golden. Once done, remove from heat and let it sit for a minute. Serve warm, sprinkled with powdered sugar and strawberry preserves on the side if desired. The total preparation time is about 10 minutes, with cooking taking another 10 minutes, making the whole process around 20 minutes.