In a tall cup (using a hand blender) or blender cup, add mustard, shallots, soy and vinegar. Blend and drizzle in 1 cup of oil to emulsify. Season with pepper and a little salt. Check for seasoning. Set aside at room temperature. Using a hot non-stick pan, coat with remaining oil and saute garlic for 2 minutes. Add shiitakes and cook until soft, about 4 minutes. Add corn and saute for 3 minutes. Deglaze with vinaigrette and just heat. In a large bowl, place frisee and pour hot vinaigrette over. Mix well and serve immediately.
PLATING Place in a large salad bowl and garnish with fresh cracked black pepper.