In a large bowl, mix the minced meat with crushed garlic, spices, salt, black pepper, and baking soda.
Gradually pour in the beef broth. Knead the meat vigorously by hand for at least 10 minutes. A sticky, homogenous mixture that 'holds its shape' will form.
Cover the bowl and let it rest in the refrigerator for at least 12, ideally 24 hours. This allows the flavors to meld and the baking soda to 'do its job'.
Preheat the grill to high heat. The Mici must go directly onto a hot grate/pan. Grill them directly over the coals so that a crust forms quickly on the surface.
Grill the rolls on all sides until they are evenly brown and cooked through, usually 3-5 minutes per side (10-15 minutes total).
Serve the Mici immediately, hot off the grill. The traditional accompaniment is Dijon or whole-grain mustard, bread, and sliced onion.