1) For amaranth risotto, heat olive oil and butter over medium heat in a large pot. Once hot, add onions and season with a pinch of salt. Cook until onions start to soften, 3-4 minutes.
2) Add amaranth to the pot and stir to combine. Then add warmed broth to the pot with the amaranth and stir to combine. Return to medium-low heat and let simmer until amaranth is tender, 20-25 minutes. It should soak up most of the liquid during cooking. If it looks dry at any point, add more liquid.
3) When amaranth is tender, season risotto with lemon juice and salt and pepper. Serve the cooked risotto with the sauteed mushrooms and garnished fresh parsley and parmesan cheese.
For sauteed mushrooms, slice mushrooms. Heat olive oil and butter over medium-high heat in a large skillet. Add mushrooms and let cook, stirring occasionally, until mushrooms loose their liquid, about 8-10 minutes.
Then add lemon juice, a pinch of red pepper flakes, and season with salt and pepper.
Serve sauteed mushrooms over amaranth.