1. Set aside cup (175 mL) microgreens for garnish. Lay 4 bread slices on a cutting board. Spread with mustard. Sprinkle half the cheese on the 4 bread slices. Top each with 1 to 2 ham slices. Divide remaining greens between slices. Sprinkle with remaining cheese. Top each stack with a bread slice and press down.
2. Whisk eggs with milk, nutmeg and salt in a shallow pie plate or square baking dish.
3. Melt 1 tbsp (15 mL) butter in a large, wide frying pan set over medium heat. When butter is almost melted, dip both sides of 1 sandwich in egg mixture, allowing sandwich to soak for a maximum of 10 seconds. When both sides have been dipped, add sandwich to the frothy butter in pan. Repeat for a second sandwich. Cook until bread is golden, 3 to 5 minutes per side. Remove to plates. Repeat for second pair of sandwiches, with additional 1 tbsp (15 mL) butter.
4. Slice sandwiches in half and top with reserved greens. Serve immediately with jam alongside, if you like.