Preheat the oven

• Preheat the oven to 180 °C.

Cook the pasta

• Cook the pasta in salted water according to the package instructions until al dente.
• Drain well and set aside.

Make the roux

• Melt the butter in a saucepan over medium-high heat.
• Whisk in the flour and cook, whisking continuously, until light golden.

Add the milk

• Gradually pour in the milk, whisking constantly to prevent lumps.
• Keep whisking until the mixture is smooth and starts to thicken.

Build the cheese sauce

• Reduce the heat to medium and stir in the gochujang and kimchi juice.
• Add three quarters of the cheddar and mozzarella and stir until fully melted and smooth.

Season the sauce

• Season with salt and white pepper to taste and adjust as needed.

Combine pasta, kimchi and sauce

• Mix the cooked pasta and kimchi in a large pot or mixing bowl.
• Pour the cheese sauce over and stir until everything is evenly coated.

Assemble and top

• Transfer the mixture to an oven-safe dish.
• Scatter the remaining cheddar and mozzarella on top.
• Finish with the panko breadcrumbs and Korean chilli flakes.

Bake

• Bake until the top is golden brown and the sauce is bubbling.