Welcome to 5-Ingredient Costco Dinners: From Costco Cart to Table – a recipe series where every dish is built (almost) entirely from Costco ingredients, comes together fast, and actually tastes like something you’d be proud to put on the table. No stress, no fancy technique, no 47-step instructions. Just good food.
This is Recipe #1 – and it’s a great place to start. One pan, 40 minutes, and a Dijon mustard trick that makes people think you actually know what you’re doing in the kitchen.
Ingredients
Kirkland Signature Boneless Skinless Chicken Thighs
Thighs are the right call here, full stop. They stay juicy even if you get distracted – breasts will dry out and you’ll be sad.
Kirkland Signature Baby Potatoes
The mixed color ones from the produce section. Small, fast-roasting, and they look great on the pan.
Kirkland Signature Organic Baby Spinach
Yes, spinach on a sheet pan. It sounds wrong and works perfectly. Trust it.
Fresh lemons
Just one – you’ll use both the zest and the juice. Costco sells them by the bag, so you’ll have plenty left over.
Grey Poupon Dijon Mustard
The ingredient that makes people ask what your secret is. At Costco if your location carries it – otherwise any grocery store. Keep a jar in the fridge permanently.
Kirkland Signature Extra Virgin Olive Oil, Kirkland Himalayan Pink Salt, black pepper, Christopher Ranch Colossal Garlic (freeze what you don’t use – frozen cloves go straight to the cutting board), and Kirkland Grass-Fed Butter.
Method
- Start the potatoes. Crank your oven to 425°F – hot oven, crispy results, that’s the whole deal. Smash 5 or 6 garlic cloves with the flat of a knife until they crack open. Halve the baby potatoes and dump them onto a large sheet pan with the garlic, a generous glug of olive oil, a good pinch of salt, and plenty of pepper. Toss with your hands until well coated, spread them cut-side down in a single layer, and into the oven for 15 minutes.
- Prep the chicken. While the potatoes get a head start, pat the thighs dry with a paper towel – wet chicken steams, dry chicken browns. Zest the lemon over the thighs, squeeze over about half the juice, and season generously with salt and pepper. Then spread a thin but confident layer of Dijon over the top of each thigh with the back of a spoon. Cover every bit of that surface.
- Roast it all together. Pull the pan out, give the potatoes a quick toss, and nestle the thighs among them, mustard-side up. Squeeze the remaining lemon half over everything. Back in the oven for 20 to 25 minutes, until the chicken is cooked through and the mustard crust is deeply golden and fragrant.
- Wilt the spinach and serve. Pile the baby spinach right on top – it looks like way too much and wilts to almost nothing in 2 minutes – and slide the pan back in just until the spinach is wilted and glossy. Serve straight from the pan.
Mustard crust not as golden as you’d like when the chicken is done? Hit it under the broiler for 2 to 3 minutes – don’t walk away, broilers move fast. And if the garlic cloves get very dark and caramelized, that’s not a mistake, that’s a bonus: they turn sweet and jammy and are delicious spread onto the chicken or potatoes.
Swaps & substitutions
- Swap the veg?
- Costco’s baby bell peppers cut in half, or the big bag of broccoli florets, both work beautifully. With broccoli, add it at the same time as the chicken since it roasts faster than potatoes.
- Swap the protein?
- Kirkland salmon fillets with the same Dijon and lemon treatment are outstanding. Add the salmon at the same time as the spinach – it only needs 12 to 15 minutes at 425°F and you really don’t want to overcook it.
Scatter a big handful of pitted kalamata olives over the pan in the last 10 minutes. They get warm and slightly jammy in the oven and add a briny, Mediterranean hit that makes this feel like a completely different – and much more impressive – dish. Grab them at Costco if your location carries them, or any grocery store.
Nutrition
- 540Calories
- 43gProtein
- 28gCarbs
- 27gFat
- 5gFiber
- 780mgSodium
