Drain and rinse amaranth. Combine with one cup water and pinch of salt. Bring amaranth to a boil, and reduce to a simmer (all the way to low.) Cover and let simmer for 15 minutes. Remove from heat and let sit for 10 more minutes to thicken amaranth.
In a separate pot add blueberries, maple syrup, and 1 tablespoon of heavy cream. Scrap out vanilla bean and toss both the seeds and the pod into the blueberries. Heat over low until blueberries are heated through (making sure not to boil the heavy cream.)
Serve by pouring blueberry liquid in the bottom, followed by amaranth, then top with blueberries.
Notes
I have to imagine this would work well with any type of berry!