This makes a nice relish, and can be served alongside meats or vegetarian entrees. Serve it chilled or at room temperature

1 c apple cider vinegar
1/3 c dark brown sugar
1 c water
4 c trimmed, chopped rhubarb
4 c chopped, washed spinach
1/2 chopped onion
1/4 t salt
1/2 t ground allspice

1. Combine vinegar, sugar, and water in a large sauce pan or Dutch oven. Bring to a boil, stirring occasionally, until the sugar is dissolved.

2. Reduce heat and stir in the rhubarb, spinach, onion, salt, and all-spice. Cover and simmer for about 30 minutes, stirring occasionally. Uncover, turn the heat up so that  the mixture is at a steady boil, and cook, stirring frequently, until thick and syrupy, about 15 minutes.  Cool to room temperature or cool then refrigerate before serving. Refrigerate leftovers.