Preheat oven to broil for egg, to 425 deg. F. for tofu. You will need to grease a large oven-safe skillet for this recipe, or bake in a greased pie plate.
Peel and grate 1/4-1/3 cup horseradish. Mix with 1-1 1/2 TB apple cider vinegar.
Wash, remove large ribs from, and chop 1/2 lb. kale or mustard greens.
In a frying pan over high heat warm 1 TB olive oil. When the oil ripples, add the greens and sauté 5-7 minutes until soft.
Dairy: Whisk together 6 eggs, 2 TB milk or cream, 1/4 tsp. salt, a pinch of dried oregano, a pinch of coarsely ground black pepper, and a pinch of ground paprika. Fold in horseradish.
Non-Dairy: Purée 16 oz. silken tofu, 1/3 cup nutritional yeast, 1 tsp. granulated onion powder, 1/2 tsp. garlic powder, 1/4 tsp. salt, 1/8 tsp. dried oregano, 1/8 tsp. coarsely ground black pepper, and 1/8th tsp. ground paprika. Fold in horseradish.
Pour batter into prepared oven-safe dish. Top with kale or mustard greens.
Broil egg frittata 5-7 minutes, until lightly browned on top and cooked through (can be lifted from pan with a turner). Remove from pan to serving plate, slice in fourths or eighths.
Bake tofu frittata 25-35 minutes, until lightly browned on top and cooked through. Slice in fourths or eighths and lift from pan.