Step 1

Place grits in medium bowl, whisk in boiling water, and let stand until water is mostly absorbed, about 10 minutes. Stir in masa harina, cover, and let cool to room temperature, about 20 minutes. Meanwhile, place husks in large bowl, cover with hot water, and let soak until pliable, about 30 minutes.

Step 2

Process masa dough, corn, butter, lard, sugar, baking powder, and salt together in food processor until mixture is light, sticky, and very smooth, about 1 minute, scraping down sides as necessary. Remove husks from water and pat dry with dish towel.

Step 3

Working with 1 husk at a time, lay on counter, cupped side up, with long side facing you and wide end on right side. Spread ¼ cup tamale dough into 4-inch square over bottom right-hand corner, pushing it flush to bottom edge but leaving ¼-inch border at wide edge. Mound 2 scant tablespoons filling in line across center of dough, parallel to bottom edge. Roll husk away from you and over filling, so that dough surrounds filling and forms cylinder. Fold up tapered end, leaving top open, and transfer seam side down to platter.

Step 4

Fit large pot or Dutch oven with steamer basket, removing feet from steamer basket if pot is short. Fill pot with water until it just touches bottom of basket and bring to boil. Gently lay tamales in basket with open ends facing up and seam sides facing out. Cover and steam, checking water level often and adding additional water as needed, until tamales easily come free from husks, about 1 hour. Transfer tamales to large platter. Reheat remaining sauce from filling in covered bowl in microwave, about 30 seconds, and serve with tamales.