. Prepare the Egg Mixture:

• In a shallow dish, whisk together the milk, eggs, salt, and pepper. Set aside.

2. Flatten the Bread:

• Lay each slice of bread on a clean surface and gently flatten with a rolling pin until thin.

3. Make the Filling:

• In a bowl, mix the diced mushrooms, shredded Swiss cheese, crumbled bacon (if using), and sliced green onions.

4. Assemble the Roll-Ups:

• Place 2 teaspoons of the filling onto one end of each flattened bread slice.
• Roll the bread tightly around the filling and place seam-side down on a cutting board.
• Cut each roll in half to make bite-sized pieces.

5. Coat the Roll-Ups:

• Dip each roll half into the egg mixture, ensuring it’s fully coated.
• Stand the rolls upright in a greased 8-inch baking dish.

6. Refrigerate:

• Pour the remaining egg mixture over the rolls. Cover with foil and refrigerate for at least 1 hour or overnight.

7. Bake:

• Preheat the oven to 350°F (175°C).
• Bake the roll-ups covered for 25-30 minutes.
• Remove the foil, dot the tops with butter, and bake uncovered for an additional 10 minutes until golden brown.

8. Serve:

• Let the roll-ups cool slightly before serving. Garnish with fresh parsley or chives and enjoy warm.