Combine the brown rice, glutinous rice, red quinoa, and black rice (total 3¼ cups). Rinse the grains and seeds carefully, gently pouring out the milky water. Repeat until the water runs clear.
2
Add 3 cups of water to the pressure cooker with the grains. (Alternatively, if using a regular pot, soak overnight or at least 3 hours beforehand, then cook according to a multigrain rice recipe.)
3
Cook the grains using an electric rice cooker or pressure cooker until done.
4
Spread the cooked grain mixture evenly on a 16×12-inch baking sheet lined with parchment paper. Lightly sprinkle with water and press down firmly with your hand or scraper to flatten and compact the grains.
5
Place the baking sheet in the middle rack of a preheated 400°F oven and bake for 1 hour.
6
Flip the nurungji using a scraper or knife, ensuring even browning on both sides.
7
Continue baking for another 30 minutes until golden, crispy, and fragrant with a toasted, nutty aroma.
8
Cool the nurungji completely and store in an airtight container or zip-lock bag for later use.
9
To make nurungji soup: Add pieces of nurungji to a pot with approximately 2 cups of cold water. Cover and bring to a boil over high heat. Simmer for about 12 minutes, then reduce heat and continue simmering until the desired thickness is reached (about 10 minutes or longer).
10
Serve hot in a bowl alongside pan-fried dried anchovies, pickled vegetables, or other traditional Korean side dishes.