Preheat oven to 350 degrees. Put the amaranth in a bowl. Saute onion in 1 Tbsp. oil. Add shallots to the amaranth, mix in lemon juice, garlic, mustard, and 3 Tbsp. of oil to make a smooth sauce. Pat the chicken dry and press into sauce until chicken is coated. Place on baking sheet and bake for 50-60 minutes. Serve with rice.