Bring 1 cup of red wine vinegar to a boil in a saucepan. Remove from heat, add 2/3 cup yellow mustard seeds, cover, and let soak at room temperature for about 90 minutes to soften.

Rinse 2¾ cups of cranberries thoroughly, discarding any that are dull or damaged. Use frozen cranberries directly from the freezer or fresh if preferred.

Transfer the soaked mustard seeds and their liquid to a food processor. Add 1 cup water and 1 tablespoon Worcestershire sauce. Pulse until the seeds are chopped but still slightly chunky.

Add the rinsed cranberries to the food processor. Pulse until the cranberries are finely chopped, maintaining a chunky texture.

Pour the mixture into a small saucepan and bring to a boil over medium-high heat, stirring regularly. Reduce heat and simmer for 5 minutes to blend the flavors.

Stir in ¾ cup sugar, ¼ cup dry mustard, and 2½ teaspoons allspice or nutmeg (if using). Mix well to incorporate all ingredients.

Continue cooking the mixture over medium-high heat for 15 minutes, stirring frequently, until it thickens to a paste-like consistency.

Sterilize your jars by washing them in hot, soapy water and inspecting for any cracks. Place the jars in a water canner and bring to a simmer. Simultaneously, soften the lids by placing them in boiling water.

Using a jar lifter, remove the hot jars from the canner. Fill each jar with the hot mustard mixture using a canning funnel, leaving ¼ inch of headspace. Remove air bubbles by running a knife around the inside edge and wipe the rims clean with a damp paper towel.

Secure the lids with rings, tightening until finger-tight. Place the filled jars back into the water bath canner, ensuring they are submerged by at least an inch of water. Process for 10 minutes, adjusting for altitude if necessary.

After processing, turn off the heat and let the jars sit in the canner for 5 minutes. Remove them using the jar lifter and place them on a cutting board to cool completely for 24 hours.

After 24 hours, check each lid by pressing the center. It should not move or pop back. Label the jars with the date and store them in a cool, dark place. Refrigerate any jars that haven’t sealed properly and consume within a few days.