Prepare the Gravy: In a small saucepan, combine all the gravy ingredients except the salt. Bring to a boil over medium-high heat, stirring occasionally. Reduce the heat and let the gravy simmer until slightly thickened, about 20 to 25 minutes. Adjust salt to taste.

Make the Meatballs: While the gravy simmers, mix the ground beef, egg, salt, and pumpkin pie spice (if using) in a large bowl. Combine thoroughly with your hands.

Divide the meat mixture into 4 equal portions, then divide each portion into 4 smaller pieces, forming a total of 16 meatballs.

Heat the tallow in a large cast-iron skillet over medium-high heat until just beginning to smoke. Swirl the pan to coat evenly with the fat.

Add the meatballs to the skillet and brown them for about 8 minutes, turning every 2 minutes to ensure even cooking.

Reduce the heat to medium and cook the meatballs for another 4 to 6 minutes, turning occasionally, until fully cooked. The internal temperature should reach 160°F.

Serve the meatballs immediately with the gravy poured over them.