A perfect holiday scalloped potatoes should be ultra-creamy inside, evenly tender from edge to center, and finished with a burnished top that stays neat when sliced. This version uses thinly sliced Yukon Golds for natural silkiness, a stabilized cream sauce (no curdling, no greasy separation), and a two-stage bake—covered to steam and soften, uncovered to brown gently. The result is a polished, restaurant-caliber side that holds up on a buffet and reheats beautifully.
Ingredients & Measurements
- Yield: 1 pan (23 × 33 cm / 9 × 13 in), 8–10 servings
- Potatoes & Aromatics
- 1.8 kg (4 lb) Yukon Gold potatoes, peeled and sliced 2 mm (1/16 in) thick
- 1 small yellow onion, very finely minced (about 120 g / ¾ cup)
- 2 garlic cloves, very finely minced
- 1 Tbsp fresh thyme leaves or 1 tsp dried thyme
- Cream Sauce (Stabilized)
- 45 g (3 Tbsp) unsalted butter
- 30 g (¼ cup) all-purpose flour (use 1:1 GF blend for gluten-free)
- 720 ml (3 cups) whole milk, room temperature
- 240 ml (1 cup) heavy cream (double cream)
- 1 tsp Dijon mustard (subtle, for balance; won’t taste “mustardy”)
- 1¼–1½ tsp fine sea salt, divided (start low; see Steps)
- ½ tsp freshly ground black pepper
- ¼ tsp ground nutmeg (optional, classic)
- Finish (Optional but Lovely)
- 30 g (¼ cup) finely grated Parmesan or Gruyère for a lightly gratinéed top
- 1 Tbsp unsalted butter, cut into small dots
- 1 Tbsp chopped parsley or chives, for serving
Step-by-Step Instructions
- Preheat and prep the pan. Position a rack in the middle of the oven and preheat to 180°C / 350°F. Lightly butter a 23 × 33 cm (9 × 13 in) baking dish. If your oven runs cool, place a preheated sheet pan on a lower rack to even out heat and catch any drips.
- Slice potatoes uniformly. Peel and slice potatoes 2 mm (1/16 in) thick using a mandoline or sharp knife. Keep slices stacked in neat piles; do not soak in water—soaking leaches starch you need for body.
- Make the stabilized cream base (no splitting). In a medium saucepan over medium heat, melt 45 g butter. Add onion and a pinch of salt; cook 3–4 minutes until translucent. Stir in garlic and thyme; cook 30 seconds. Sprinkle in flour; whisk and cook 60–90 seconds to a blond roux. Gradually whisk in milk, then cream, whisking constantly until smooth. Add Dijon, 1 tsp salt, pepper, and nutmeg. Bring to a gentle simmer and cook 3–4 minutes more, whisking, until the sauce lightly coats a spoon. Take off heat.
- Layer for even cooking. Spread a thin film of sauce in the dish. Arrange one-third of the potatoes in overlapping shingle rows. Season lightly with a pinch of salt (remember the sauce is seasoned). Ladle over one-third of the sauce. Repeat two more layers, finishing with sauce. Gently jiggle the pan to settle.
- Cover and steam. Cover tightly with foil (tent slightly so foil doesn’t touch the sauce) and bake 40–45 minutes. This stage softens the center without over-browning the top.
- Uncover and finish to golden. Remove foil, dot the surface with 1 Tbsp butter, and (if using) sprinkle Parmesan/Gruyère evenly. Continue baking 25–30 minutes, until the top is deep golden and a knife slides through the center with no resistance. Total bake time is typically 65–75 minutes, depending on slice thickness and pan material.
- Rest for clean slices. Transfer to a wire rack and rest 15–20 minutes. This crucial pause allows the cream to thicken slightly so portions cut cleanly and don’t slouch on the plate.
- Serve and garnish. Sprinkle with chopped parsley or chives. Cut into rectangles or spoon into warm bowls. The texture should be tender, creamy, and cohesive with distinct, soft layers.
- Hold & reheat for service. To hold up to 45 minutes, keep covered loosely in a 90–95°C / 195–200°F oven. For reheating, cover with foil and warm at 165°C / 325°F for 20–25 minutes until hot in the center (an instant-read thermometer should read 75°C / 167°F).
Cooking Notes
- Potato choice: Yukon Golds give a naturally buttery texture and keep their shape. Russets work but release more starch; if using russets, slice slightly thicker (2.5–3 mm) to avoid collapsing layers.
- Why a roux? Traditional scalloped potatoes can split if cream boils hard. A brief flour + butter roux plus milk/cream keeps the emulsion stable and reheatable without separating.
- Seasoning discipline: Potatoes mute salt. Taste the finished sauce before layering; it should be pleasantly seasoned but not salty. You’ll add only pinches between layers.
- Cheese or not? Strictly, scalloped potatoes are cheese-free; au gratin includes cheese. The optional 30 g Parm/Gruyère adds savory depth without turning this into a heavy gratin.
- Thickness & doneness cues: Slices at 2 mm deliver even tenderness. If you sliced thicker, extend both the covered and uncovered stages by 5–10 minutes each; judge with the knife test.
- Make-ahead (two options):
- Assemble ahead: Build the dish up to Step 4, cool the sauce slightly first, cover, and refrigerate up to 24 hours. Bake cold, adding 10–15 minutes to the covered stage.
- Bake ahead: Fully bake, cool 45 minutes, cover, and refrigerate up to 2 days. Reheat covered at 165°C / 325°F for 25–35 minutes, then uncover 5 minutes to refresh the top.
- Gluten-free path: Use a 1:1 GF flour blend for the roux or skip the roux and whisk 1 Tbsp cornstarch into 60 ml (¼ cup) cold milk; stir into the hot sauce at the end and simmer 1 minute until lightly thickened.
- Lighter variation: Replace the cream with evaporated milk (full-fat). Body remains silky with fewer calories; keep the simmer gentle to prevent curdling.
- Flavor riffs:
- Leek & Gruyère: Swap onion for 2 cups thinly sliced leeks; use Gruyère on top.
- Garlic-Herb: Increase garlic to 3–4 cloves and add 1 tsp chopped rosemary with thyme.
- Smoky bacon: Scatter 4 crisp-cooked, crumbled bacon between layers; reduce added salt slightly.
- Pan choices: Light-colored ceramic or glass browns gently; metal browns faster. In a dark metal pan, start checking uncovered stage 5 minutes earlier.
- Buffet service: For neat squares on a buffet, cool baked casserole 25–30 minutes, then cut and transfer portions to a warm platter; the structure holds and stays creamy.
- Food safety: Don’t leave dairy-based casseroles at room temperature for more than 2 hours. Cool leftovers quickly; store airtight 3–4 days.
Nutrition Facts (per serving)
- Serving size: 1/10 of pan
- Approximate calories: 310 kcal
- Total fat: 16 g
- Saturated fat: 10 g
- Carbohydrates: 33 g
- Dietary fiber: 3 g
- Total sugars: 6 g
- Protein: 8 g
- Sodium: 410 mg
Conclusion
These Creamy Scalloped Potatoes bring reliable texture and holiday polish to your table: evenly cooked layers, a stable, silky sauce, and a golden top that slices cleanly after a short rest. With precise slicing, a gentle roux-based cream, and a two-stage bake, you’ll get consistent results that travel and reheat well—an ideal classic Christmas side that complements everything from prime rib to glazed ham.
