Cut cauliflower into florets, place in a large pot. Pour water, just to cover all cauliflower florets. Add 1/2 teaspoon salt, keep remaining salt for the sauce.
Start cooking on medium-high heat, once it starts to boil, lower the heat and cook for 10 minutes.
In the meantime, heat large frying pan, add bacon slices, cook for 3-5 minutes on each side. Remove bacon from the pan and cut into small pieces, set aside.
Drain cauliflower when it's done cooking.
Keep 4 tablespoons of bacon dripping on the large frying pan, discard the rest. Add flour to the frying pan, cook for 1-2 minutes on low-medium heat, mixing all the time.
Whisk in the milk, add 1/2 teaspoon salt, garlic powder and mustard powder. Cook on low heat, mixing often until thickens for about 2-3 minutes.
Remove the sauce from heat, add 1 cup of cheddar cheese and dill, mix it.
Preheat oven to 350 F.
Place cauliflower florets in the deep baking pan, pour sauce. Top it with remaining cheddar cheese and bacon. Bake for 15-20 minutes until bubbly and cheese is melted.