Place cauliflower florets in lg saucepan.  Fill saucepan with water until cauliflower is just covered.  Add 1/4 tsp salt.  Bring to boil and cook until cauliflower is soft, approx. 20 min.

Drain cauliflower in colander and return to saucepan.  Add butter, milk, garlic powder, remaining salt, and cheddar.  Mash with potato masher until smooth.