Step 1

You can substitute leftover poached or grilled chicken for the rotisserie chicken, if desired.

Step 2

Melt butter in large saucepan over medium heat. Add onion and cook until softened, about 4 minutes. Increase heat to medium-high; add broth, thyme sprigs, 1 teaspoon salt, and ½ teaspoon pepper; and bring to boil. Add orzo and cook until tender, 12 to 14 minutes. Remove from heat and discard thyme sprigs.

Step 3

Whisk egg yolks and lemon juice in bowl until combined. Whisking constantly, slowly pour yolk mixture into hot soup. Stir in chicken, cover, and let sit for 10 minutes, until soup is thickened and chicken is warmed through. Sprinkle with chives. Serve.