Start by trimming the ends of the Brussels sprouts and removing any loose or wilted leaves to ensure they cook evenly. Wash the sprouts under cold water to get rid of any dirt, then pat them dry with a kitchen towel.

In a large pot, bring salted water to a rolling boil. Add the trimmed Brussels sprouts and let them cook for about 10–12 minutes, or until they are fork-tender but still vibrant green.

In a medium saucepan over medium heat, melt 2 tablespoons of butter until bubbly. Sprinkle in 2 tablespoons of all-purpose flour, stirring constantly for around 1.5 minutes to create a roux.

Gradually pour in 1 cup of milk while whisking continuously, and cook the mixture for about 5 minutes until it thickens.

Remove the saucepan from the heat and stir in 2 tablespoons of honey Dijon mustard, along with salt and pepper to taste, then mix in ½ cup of shredded cheddar cheese.

Pour the boiled Brussels sprouts into the cheese sauce and gently stir to coat them evenly. Transfer the mixture to a greased 11x7-inch baking dish.

Preheat your oven to 375°F (190°C). Sprinkle the remaining cheddar cheese over the top of the Brussels sprouts mixture and bake for approximately 25 minutes, until the cheese is bubbly and golden brown.