Make a Cauliflower Cheese Side Dish

Name: Make a Cauliflower Cheese Side Dish
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Cuisine: American, British, Southern
Ingredients: 1 medium cauliflower (approximately 1lb./450 g); 2 oz./55 g butter; 2 oz./55 g all-purpose flour; Optional: 1 tsp. mustard powder; 1 pinch salt (to taste); 2 cups/460 mL milk; 2 oz./55 g cheddar cheese (or similar, grated, plus extra for sprinkling on top); Freshly ground pepper (to taste)