1 stalk rhubarb (about 2 ounces), cut into 1/4- to 1/2-inch dice to yield 1/2 cup
4 to 6 large strawberries, hulled and cut into 1/4- to 1/2-inch dice to yield 1/2 cup
1 small onion, cut into small dice (1/2 cup)
1 cup sugar
2 teaspoons mustard seeds
1/2 teaspoon salt, divided
2 tablespoons apple-cider vinegar
8 scallions (root ends trimmed off), remaining white and light-green parts about 6 inches long
3/4 pound peeled and cored pineapple, cut into four 1/4- to 1/2-inch slices
8 bone-in, skinless chicken thighs (about 2 pounds)
Freshly ground black pepper, to taste

Combine the rhubarb, strawberries, onion, sugar, mustard seeds, 1/4 teaspoon of the salt and 1 cup water in a small saucepan over medium to medium-high heat. Stir to mix well until bubbles form at edges. Cook for 45 minutes, stirring occasionally and making sure mixture does not boil over, until it has reduced by half; vegetables should be quite soft.

Carefully transfer to a blender. Remove center portion of lid to let steam escape, then place a dish towel over lid. Puree until smooth, then add the vinegar and pulse to combine. Divide glaze evenly between 2 small bowls.

Prepare grill for direct and indirect heat. If using a gas grill, preheat to medium (350 F). If using a charcoal grill, light charcoal or wood briquettes; when briquettes are ready, distribute them on one side of cooking area. For a medium-hot fire, you should be able to hold your hand about 6 inches above coals for about 6 or 7 seconds. Have ready a spray water bottle for taming any flames. Lightly coat grill rack with oil and place it on grill.

While grill is preheating, bring a shallow pan of lightly salted water to a boil over medium-high heat. Add the scallions and cook for 2 minutes (for thin scallions) to 4 minutes (thick), then use tongs to transfer them to a plate. They should be tender and bright green.

With remaining 1/4 teaspoon salt, lightly salt the pineapple slices and chicken thighs; season chicken with the pepper to taste. Place them on grill over direct heat; close lid. When pineapple has good grill marks on one side (5 to 6 minutes), turn pieces and move to indirect-heat side of grill.

Use one bowl of glaze to brush pineapple. Grill (with lid closed) for 5 to 6 minutes. At the same time, turn over chicken thighs once they have grill marks (10 to 13 minutes), allowing second side to get color and grill marks (10 to 12 minutes). Then transfer to indirect-heat side of grill and brush with glaze in second bowl.

As pineapple and chicken thighs are done, transfer them to a platter; use space on grill rack to grill par-cooked scallions close to indirect-heat side of grill just for a few minutes, until they are slightly charred.

To serve, cut each slice of grilled pineapple in half, placing a half-slice on each plate. Top with 2 grilled chicken thighs, 2 grilled scallions and a second pineapple half.

Makes 4 servings.

NOTE: If you happen to have strawberry-rhubarb jam, you can substitute 3/4 cup of it for the strawberries, rhubarb, water and sugar. Just combine jam with the onion and mustard seeds and cook for about 25 minutes, until onions are soft.