Heat oven to 425
Peel two large russet potatoes and 2 large yams chop into generous 1" cubes
In a large mixing bowl mix 3 TBLS of olive oil, 3 TBLS of Dijon mustard, 3 cloves crushed garlic
Toss potato and yam cubes in oil mixture until thoroughly coated.
Lay in single layer on a greased cookie sheet.
Bake for 30 minutes, remove and stir, bake an additional 15-30 minutes or until outside of potatoes is golden and inside is very soft.
Salt and pepper to taste.