Rinse heart or tongue with cold water. With a small knife make 6 to 8 small slits in various places on heart or tongue, fill each with a clove of garlic.
Place in a 6 quart pressure cooker. Pour cider vinegar into pressure cooker to make it 1/2 full. Add a few more garlic cloves and at least 1 onion, cut up or sliced. Add water to make the pressure cooker 3/4 full; add a handful of pickling spice.
Put lid and valve on cooker and cook on high heat until the valve rocks vigorously, then lower to a low to medium heat and cook for 40 minutes. Cool. Remove from liquid, slice and return to liquid. Store in a bowl in refrigerator. PLEASE NOTE: For tongue you must peel off the skin before slicing. When thoroughly chilled skim off any excess fat.
