Prepare the Curry Filling: If you have leftover Japanese curry from last night’s dinner—perfect! If not, make a small batch using onions, carrots, potatoes, curry roux, and your choice of protein. For this sandwich, I sometimes add cooked ground beef or beef sausage for extra richness. Simmer the curry until thickened—you want it spoonable, not runny.

Butter the Bread: Butter one side of each bread slice. This will help achieve that classic grilled cheese crunch. Use a thick sandwich bread like shokupan, brioche, or sourdough for the best texture.

Assemble the Sandwich: Lay one slice of bread, butter-side down, in a skillet or on a cutting board. Add a layer of shredded cheese, then a generous scoop of curry (avoiding too much liquid), and another layer of cheese on top. Cap it with the second slice of bread, butter-side up.

Toast to Perfection: Heat a skillet over medium-low heat. Place your sandwich in the pan and cook for 3–4 minutes per side, pressing gently with a spatula. The goal is golden-brown bread and melted cheese. Be patient—it’s worth it.

Slice and Serve: Let it rest for a minute before slicing. This helps the cheese settle slightly. Then cut it in half and serve while hot, with extra curry on the side if you like.