Bring the water with the soup spices and amaranth to a boil and simmer gently for 30 minutes with the lid closed. Stir every now and then towards the end and leave to soak for another 5 minutes.
In the meantime, thaw the frozen spinach leaves with 50 ml water and simmer gently. Soak the dried tomatoes in warm water for 5 minutes, cut the garlic or garlic into small pieces and add to the simmering amaranth in the pot.
Preheat the oven to 180 ° C. Put the butter and frozen boletus in a pan and fry over high heat until the liquid has evaporated. Drain the spinach leaves well in a colander. Everything will be done at the same time! Dice the feta and tomatoes, set aside. Return the spinach leaves to the pot, add the mushrooms and amaranth and mix everything together. Stir in the spices, cream and diced feta.
Pour into an oiled baking dish, distribute the tomatoes and grated cheese evenly on top. Bake for 10 minutes at 180 ° C fan oven. Can also be warmed up.