Meatballs with Hidden Heart and Liver

Method

1. Partially freeze the liver for 20 to 30 minutes, then purée it in a blender or grate it finely. If your butcher sells ground heart, use it; otherwise pulse trimmed heart in a food processor until it looks like ground beef.
2. In a large bowl, combine the ground beef, heart, liver purée, and salt. Mix with your hands just until evenly combined. Overmixing makes meatballs dense.
3. Wet your hands and roll into 20 meatballs of about 1.5 in.
4. Heat the oven to 400°F (200°C). Brush a sheet pan with the tallow and space the meatballs on it.
5. Bake 18 to 22 minutes, turning once, until browned.
6. Check a few with a thermometer: ground meat and any mixture containing ground organ meat should reach 160°F (71°C).