Wasabi Mashed Potatoes

Place potatoes in large pot of cold salted water. Boil until tender, about 20 minutes. Drain. Return to pot; mash.
 
Combine 3/4 cup milk and 1 tablespoon wasabi powder in small bowl. Stir to dissolve powder. Add milk mixture and butter to potatoes. Using electric mixer, beat potatoes until fluffy and smooth. Season potatoes to taste with salt and pepper. (Can be prepared 2 hours ahead. Cover and keep at room temperature. Rewarm mashed potatoes over low heat, stirring frequently.)