Grandma’s Scalloped Potatoes

These aren’t just any scalloped potatoes – they’re the kind that make people close their eyes and sigh happily at first bite. Layers of perfectly tender potatoes swimming in a rich, garlicky cream sauce, all blanketed in melty cheese? Yes, please!

What makes these extra special is the combination of sharp cheddar and Parmesan cheeses, plus a generous amount of fresh garlic and thyme. The sauce gets velvety-smooth thanks to a proper roux base, and those Yukon Gold potatoes stay creamy without falling apart. This is the recipe that’ll have everyone begging for seconds.

Ingredients

For the Base:

• 3 tablespoons butter
• 1 small white or yellow onion, peeled and thinly sliced
• 4 large garlic cloves, minced
• 1/4 cup all-purpose flour
• 1 cup chicken stock or vegetable stock
• 2 cups whole milk (or half and half)

Seasonings:

• 1 1/2 teaspoons Kosher salt
• 1/2 teaspoon black pepper
• 2 teaspoons fresh thyme leaves, divided

Main Components:

• 4 pounds Yukon Gold Potatoes, sliced into 1/8-inch rounds
• 2 cups freshly-grated sharp cheddar cheese, divided
• 1/2 cup freshly-grated Parmesan cheese, plus extra for serving

Steps

1. Preheat and Prep: Heat oven to 400°F (200°C). Thoroughly grease a 9 x 13-inch baking dish with cooking spray. Pro tip: Choose a dish with at least 2-inch high sides to prevent overflow.
2. Create the Base: Melt 3 tablespoons butter in a large sauté pan over medium-high heat. Add onion and cook for 4-5 minutes until translucent (not browned). Add garlic and cook 1-2 minutes more until fragrant but not golden. Stir in flour and cook for 1 minute to remove raw flour taste.
3. Make the Sauce: Gradually whisk in stock (about 1/4 cup at a time) until smooth. Add milk, salt, pepper, and 1 teaspoon thyme. Cook 1-2 minutes until sauce thickens enough to coat the back of a spoon. Watch for tiny bubbles around the edge – if it boils, your sauce might break.
4. Layer with Care: Start with half the potatoes in an even layer – overlap slightly for stability. Pour half the sauce, ensuring even coverage. Add 1 cup cheddar and all the Parmesan. Repeat layers with remaining potatoes, sauce, and cheddar.
5. Two-Stage Baking: Cover tightly with foil and bake 30 minutes at 400°F (200°C). Remove foil and bake another 25-30 minutes until potatoes are tender when pierced with a knife and top is golden brown.
6. Rest and Serve: Let rest 15-20 minutes before serving. This allows the sauce to set properly. Garnish with remaining thyme and extra Parmesan just before serving.

Smart Swaps

• Use 1 cup chicken broth + 1 cup evaporated milk instead of whole milk for extra richness
• Substitute 1/2 teaspoon dried thyme for fresh (reduce amount by half)
• Try Gruyere cheese instead of cheddar for a more sophisticated flavor profile

Make It Diabetes-Friendly

• Replace potatoes with turnips or cauliflower (reduces carbs by 65%)
• Use unsweetened almond milk with 1/4 cup heavy cream instead of whole milk
• Add 1/4 teaspoon xanthan gum to thicken sauce without flour
• Portion size: stick to 1/2 cup serving (approximately 15g net carbs)

Pro Tips

• Slice potatoes with a mandoline for even cooking
• Let dish sit 10 minutes before cutting for cleaner portions
• Use room temperature dairy for smoothest sauce
• Test potato doneness in center of dish, not edges