01 - Heat olive oil and butter in a large deep skillet or Dutch oven over medium heat. Add onions, carrots, and celery. Sauté for 5–6 minutes until vegetables are soft.
02 - Stir in garlic and cook for 30 seconds until fragrant.
03 - Sprinkle flour over the vegetables, stirring constantly, and cook for 1–2 minutes to form a roux.
04 - Gradually whisk in the chicken broth and milk, stirring well to avoid lumps. Add thyme, sage, salt, and pepper. Bring to a gentle simmer until sauce thickens, about 5 minutes.
05 - Add the uncooked gnocchi, chicken, and peas. Stir gently to combine and ensure the gnocchi are submerged. Cover and simmer for 10–12 minutes, stirring occasionally, until gnocchi are cooked and sauce is creamy.
06 - Remove from heat. Stir in Parmesan if using. Garnish with fresh parsley before serving.