2 tbsp butter
2 tbsp all-purpose flour
1 tsp dry mustard powder
1-1/2 cups chicken stock
1 cup grated sharp cheddar cheese
salt and freshly ground pepper
1 lb asparagus
4 thick slices country-style bread
Melt the butter in a medium-sized saucepan, add the flour and mustard and stire to combine. Cook about 3 minutes, stirring. Remove from the heat and gradually whisk in the chicken stock. Return to the heat and bring to a boil, whisking.
Reduce the heat. Add the cheese, stirring until it is melted. Check the seasoning and keep warm. Wash and trim the asparagus and cook in simmering salted water. While the asparagus is cooking, toast the bread.
Place a piece of toast on each of 4 warmed plates. Drain the asparagus, divide between the plates and top with the cheese sauce.