Lemon and Chive Pan Sauce

The sauce is from Cook's Illustrated, but for the chicken, I follow the instructions to make Sauteed Chicken Breasts.

1 shallot, minced (about 3 tablespoons)

1 tsp all-purpose flour

1 cup low-sodium chicken broth

1 Tbsp juice from 1 lemon

1 Tbsp minced fresh chives (I've also used green onion tails)

1 Tbsp (½ oz/14gr) butter

Salt and ground black pepper

1. If required, add a little oil and sautée shallot in a skillet and cook over medium heat until softened, about 2 minutes. 
2. Add the flour and cook, stirring constantly, for about 30 seconds. 
3. Add the broth, increase the heat to medium-high, and bring to a simmer, scraping the pan bottom to loosen browned bits. 
4. Simmer rapidly until the liquid is reduced to ¾ cup, 3 to 5 minutes. Stir in any accumulated chicken juices; return to a simmer and cook 30 seconds. Off heat, whisk in the lemon juice, chives, and butter; season with salt and pepper. Spoon over chicken and serve immediately.