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