In the same pot, melt 4 Tbsp butter and whisk in 1/3 cup flour until lightly golden (1 1/2 min). Add 2 1/2 cups
chicken broth, 1 Tbsp lemon juice, 1 tsp salt, 1/4 tsp pepper and whisk until smooth. Add 1 1/2 cups half and half and bring to a simmer. Season sauce with more salt and pepper to taste.