Instructions

Adjust oven rack to middle position and heat oven to 250 degrees. Bring 2 quarts water to boil in medium pot. Add orzo and 1½ teaspoons salt and cook, stirring often, until al dente. Reserve ¼ cup cooking water, then drain pasta and return it to pot. Add spinach, 1 tablespoon oil, 1 tablespoon shallot, and lemon zest and toss to combine, adding reserved cooking water as needed until spinach is wilted. Season with salt and pepper to taste. Cover and keep warm.
Meanwhile, pat chicken dry with paper towels and season with salt and pepper. Heat 2 teaspoons oil in 12-inch skillet over medium-high heat until shimmering. Cook half of chicken until browned on both sides and cooked through, about 3 minutes per side. Transfer to platter and tent loosely with aluminum foil. Repeat with 2 teaspoons oil and remaining chicken. Transfer platter to oven to keep warm. Reduce heat to medium. Add remaining 2 teaspoons oil and remaining 2 tablespoons shallot to now-empty skillet and cook until softened, about 30 seconds. Add broth and wine and bring to simmer, scraping up any browned bits. Simmer until reduced to ½ cup, about 8 minutes. Remove from heat and whisk in butter. Season with salt and pepper to taste. Pour sauce over chicken and serve with orzo.