Ruby Tuesday type cauliflower mash

Divide a head of cauliflower into flowerets that are all roughly the same size. Steam cauliflower pieces over boiling water 15 to 20 minutes, or until the cauliflower is tender. Drain the cauliflower. Return to pan and add 1/2 cup of water, puree with stick blender but be sure to leave a few chunks. Dissolve corn starch in remaining 1/4 cup water and add the solution to the cauliflower. Add the milk, butter, salt, white pepper, garlic powder and the onion powder to the cauliflower and stir. Set the saucepan over medium heat and cook, stirring often, for 5 to 10 minutes or until thick.