Steps
1. Preheat a skillet over medium heat.
2. Make a simple béchamel sauce by melting 1 tbsp butter in a small saucepan, whisking in 1 tsp flour, then slowly adding 2 tbsp milk until smooth and thickened. Stir in shredded Gruyere cheese until melted and smooth; season with salt and pepper. Set aside.
3. Butter one side of each bread slice.
4. Place one slice, buttered side down, on the skillet. Spread the cheese fondue evenly on top.
5. Top with the second slice, buttered side up. Grill until golden brown, then flip and grill the other side until golden and cheese is melty.
6. In a separate pan, cook the egg sunny side up, seasoning with salt and pepper.
7. Place the cooked egg on top of the sandwich.
8. Garnish with freshly chopped parsley.
9. Serve immediately, enjoying the creamy Gruyere beneath the runny egg and fresh parsley on top.