Preheat a dry Dutch oven over medium-high heat for 5 minutes. Add 1 Tbsp of amaranth to the pot and quickly put the lid on the pan. The amaranth should start popping immediately. Lift the pan off the heat slightly and shake for 30 seconds to 1 minute, until you hear reduced popping, then pour into a serving bowl. If the pot isn’t hot enough the amaranth will quickly burn instead of popping. If that happens, discard, and start over. Repeat with 1-2 Tbsp of amaranth as needed for serving.

Reduce the heat to medium. Melt the butter in the same pot, add the corn kernels and sauté until they are soft and starting to brown, about 5 minutes.

Add the broth and salt to the pot, and then the rest of the un-popped amaranth. Bring to a boil, cover, reduce the heat and simmer for 10 minutes. Remove from heat and let steam for 5 minutes longer, then raise the heat to medium-low and stir in the buttermilk, masa harina and Parmesan cheese. Ladle into bowls and served with a generous portion of popped amaranth on top.