In a medium bowl or large jar, whisk together the vinegar, water, brown sugar, molasses, and salt until the sugar completely dissolves, about 1 minute.
Stir in the liquid smoke, onion powder, garlic powder, black pepper, cinnamon, and minced red bell pepper.
Optional: for a thicker, clingier marinade, whisk the cornstarch with cold water, stir it in, and warm the marinade over low heat for 1–2 minutes until just thickened. Cool completely before using.
Pour over chicken, pork, steak, salmon, or vegetables. Marinate at least 15 minutes (see post for times by protein).
Grill, bake, air fry, or slow cook, basting with fresh, unused marinade. Discard any marinade that touched raw meat.