In a medium saucepan, melt the butter over medium heat. Once it’s bubbly, add the flour, stirring constantly for about 1-2 minutes until it turns a light golden color.

Gradually pour in the milk while whisking continuously until the mixture thickens and becomes smooth, which usually takes about 3-5 minutes.

Stir in the shredded cheddar cheese until it’s all melted and gooey.

Stir in the diced ham, frozen peas, and cooked pasta (or rice) into the sauce. Mix everything gently, ensuring all ingredients are well-coated.

Pour the mixture into a greased baking dish. Spread it out evenly.

Place the dish in a preheated oven at 350°F for about 20 minutes, or until the top is bubbly and lightly golden.