Be sure to stop cooking the garlic chips when they are light golden brown. They will continue to darken and crisp as they cool. We prefer the flavor and texture of whole-grain farro in this recipe. Pearled farro can be used, but cooking times vary, so start checking for doneness after 10 minutes. Do not use quick-cooking farro. Arranging the broccoli rabe in a pile on the baking sheet creates textural contrast and prevents it from drying out. If you don't care for the bitterness of broccoli rabe, you can substitute broccolini.
Total Time: 1¼ hours
1. Adjust oven rack to upper-middle position and heat oven to 425 degrees. Heat 3 tablespoons oil and garlic in large saucepan over medium heat, stirring constantly once garlic starts to sizzle. Cook until garlic is light golden brown, 3 to 5 minutes. Drain garlic in fine-mesh strainer set over medium bowl; reserve oil. Transfer garlic to paper towel–lined plate and sprinkle with pinch salt. (Do not wash saucepan or strainer.)
2. Combine vinegar, sugar, and ½ teaspoon salt in second medium bowl. Microwave until simmering, 1 to 2 minutes. Add grapes and stir until coated. Set aside, stirring occasionally.
3. Bring 6 cups water to boil in now-empty saucepan. Add farro and 1 teaspoon salt. Reduce heat and simmer, stirring occasionally, until farro is tender, 20 to 25 minutes. Drain farro in fine-mesh strainer and return it to saucepan. Cover and set aside.
4. While farro is cooking, spray rimmed baking sheet with vegetable oil spray. Place sausages on 1 side of sheet. Toss broccoli rabe with ½ teaspoon salt and remaining 1 tablespoon oil and pile on opposite side of sheet. Spread bell peppers in middle of sheet and sprinkle with remaining ¼ teaspoon salt. Roast until vegetables are tender and browned in spots and sausages are browned in spots and register at least 160 degrees, 20 to 25 minutes, flipping sausages and stirring vegetables halfway through roasting.
5. Measure out 2 tablespoons grape liquid and add to reserved garlic oil. Whisk in mustard and 2 tablespoons water. Stir 3 tablespoons dressing into farro. Transfer sausages to cutting board. Halve sausages lengthwise and slice crosswise ½ inch thick.
6. Spoon farro into 4 wide bowls. Arrange sausage pieces, broccoli rabe, bell peppers, and grapes in piles that cover farro. Drizzle sausage pieces and vegetables with remaining dressing. Sprinkle with garlic chips and serve.