Chicken, Mushroom and Spinach Casserole
A weeknight casserole the way many of us grew up eating it here—simple, satisfying, and built from pantry staples. Tender chicken, mushrooms, and spinach tucked into a creamy sauce sparked with English mustard. It’s humble, it’s cozy, and it feeds a table without fuss.
Prep Time: 15 minutes
Total Time: 45–55 minutes
Serves: 4–6
Ingredients
800 g boneless, skinless chicken thighs, cut into large chunks
1 tbsp olive oil + 1 tbsp butter (or just oil)
1 large onion, finely sliced
300 g mushrooms, sliced (button or cremini)
2 garlic cloves, minced
1 tbsp English mustard (heaped teaspoon if strong)
1 can condensed cream of mushroom soup (284 ml)
1 cup (240 ml) chicken stock
150–200 g baby spinach
1 tsp fresh thyme leaves (or ½ tsp dried)
1–2 tsp lemon juice, to finish
salt and black pepper
Method
Heat the oven to 200°C / 400°F. season the chicken with salt and pepper.
In a wide ovenproof pan or casserole, warm the oil and butter over medium-high heat. brown the chicken in two batches, 3–4 minutes per side; set aside.
Lower the heat to medium. add the onion and mushrooms to the same pan with a pinch of salt; cook 6–8 minutes until soft and golden. stir in the garlic for 30 seconds.
Add the mustard, condensed mushroom soup, and chicken stock; whisk or stir until smooth. bring to a gentle simmer, then add thyme. taste and season.
Return the chicken (and any juices) to the pan. transfer to the oven and bake 15–20 minutes, until the chicken is cooked through and the sauce is bubbling.
Remove from the oven, fold in the spinach to wilt (1–2 minutes). finish with lemon juice, adjust salt and pepper, and serve with rice, mash, or buttered noodles.
Variations
Veg-friendly creamy mushroom bake: swap chicken for 2 cans chickpeas (drained) and 300 g extra mushrooms. use vegetable stock. add a splash of cream or milk alternative to loosen if needed.
Crispy-topped casserole: before baking, scatter over 1 cup fresh breadcrumbs mixed with 2 tbsp olive oil and a pinch of salt; bake until golden.
Winter rice one-pan: stir 1 cup parboiled or quick-cook brown rice into the sauce with an extra 1 cup stock; nestle chicken on top and bake 25–30 minutes until the rice is tender and the liquid absorbed.