Preparation

1.Preheat the oven to 375°F. Grease a 9″ × 13″ casserole dish.
2. In a skillet, heat 1 Tbsp oil (or butter) over medium heat. Sauté prepped celery and onion until soft, about 5 minutes. Set aside.
3. In a saucepan, melt 3 Tbsp butter over medium heat. Whisk in your measured flour and cook 1–2 minutes to form a roux, stirring constantly. Slowly whisk in chicken stock, then milk, until smooth. Cook, stirring, until thickened, about 5 minutes.
4. Remove sauce from heat. Stir in lemon zest, lemon juice, dried tarragon, salt, and pepper.
5. In a large bowl, combine shredded chicken, sautéed celery and onion, frozen peas, and the squeezed spinach. Pour lemon-tarragon sauce into the bowl and gently mix until everything is fully incorporated.
6. Pour saucy chicken mixture into your prepared casserole dish and spread it out evenly.
7. Arrange frozen tater tots in a single layer over the filling. Tuck them in tight. Lightly brush or drizzle melted butter over the top, if desired.
8. Bake, uncovered, for 35–40 minutes, or until the tots are golden and crispy and the filling is bubbly around the edges. Internal temperature should reach at least 165°F.
9. Rest for 5–10 minutes before serving.