Finely slice 1 small onion (3 ounces/100 grams), half a medium carrot (3 ounces/100 grams), and 1 shallot (1 ounce/25 grams). Crush and peel 1 garlic clove. Cover the aromatic vegetables with 3 cups (750 milliliters) white wine and 1 cup (250 milliliters) white wine vinegar. Add 1 small handful of parsley stems, 2 or 3 sprigs of fresh thyme, half a bay leaf, and 1 crushed clove. If the meat is to be marinated, add ½ cup (125 milliliters) extra-virgin olive oil. Store the marinade in a plastic or stainless-steel container (not aluminum, which will react with the acidity in the wine and vinegar) overnight in the refrigerator.