01 -
Heat olive oil in a medium skillet over medium heat until shimmering. Add unsalted butter and allow to melt and foam. Stir in minced garlic and cook until fragrant, about 30 seconds to 1 minute, avoiding browning.
02 -
Incorporate lemon zest into the skillet and stir for 15 to 20 seconds. Add cooked shrimp, tossing gently for 1 minute to warm and infuse flavors. Stir in fresh lemon juice, then remove from heat and set aside.
03 -
Combine grated Gruyere and mozzarella cheese in a bowl, mixing evenly to create the cheese blend.
04 -
Spread softened unsalted butter evenly on one side of each sourdough slice; this will be the exterior when grilling.
05 -
On the unbuttered side of two bread slices, evenly distribute half of the cheese blend. Layer half of the shrimp mixture atop the cheese, then sprinkle the remaining cheese blend over the shrimp. Top with the remaining bread slices, buttered side up.
06 -
Heat a large skillet or griddle over medium-low heat. Place the assembled sandwiches in the pan and cook for 4 to 5 minutes per side, ensuring bread is golden brown and cheese is melted. Adjust heat as needed to prevent burning, pressing lightly with a spatula to promote even browning.
07 -
Remove sandwiches from skillet. Sprinkle grated Parmesan cheese over the tops while still hot to adhere. Allow sandwiches to rest for one minute before slicing and serving immediately.