Most home potatoes au gratin recipes call for mincing garlic and scattering it between potato layers, or sprinkling dried herbs over the top. The problem: garlic placed raw between layers releases its flavor only in the immediate area, concentrating pungently at the bottom and staying muted near the top. Herbs scattered on the surface never penetrate the layers below.

Pre-infusing means heating the cream with garlic, thyme, salt, pepper, and a pinch of nutmeg for three to four minutes — just until steaming and fragrant, never boiling — then letting it steep for five minutes off the heat. When you pour that cream over the potato layers, every slice gets the same flavor. The garlic mellows from sharp and raw to rounded and savory. The thyme becomes a background note rather than a dominant flavor. The result is a gratin that tastes balanced and complete rather than layered in separate flavor zones.

This technique is the most common gap between restaurant au gratin and the home version. It adds eight minutes to the recipe and changes the dish.

Russet potatoes absorb liquid aggressively and are high in starch — qualities that make them excellent for mashed potatoes, where you want the potato to fall apart and take on the butter and cream. In a gratin, the same properties work against you: Russets soak up the cream, bloat, and eventually collapse into a dense, grainy layer rather than a fork-tender slice. By the time the cream has thickened around the potato, the potato itself has lost its structure.

Yukon Gold potatoes are medium-starch and waxy. They absorb the cream at a slower rate that keeps pace with the cream thickening, so by the time the dish is done, the potatoes and the sauce have reached the right consistency at the same moment. Each slice is fully tender but intact — you can see the distinct layers when you scoop out a portion, and they hold together on the plate.

If Yukon Golds are unavailable, red potatoes (also waxy and medium-starch) work well. White or “all-purpose” potatoes behave more like Russets and are not recommended.

Gruyère is the classic au gratin cheese for a specific reason: it melts smoothly and evenly without releasing the oily pools or grainy clumps that sharper, drier cheeses produce at high heat. It also forms the golden-brown crust (the literal meaning of “gratiné”) more reliably than most alternatives. The flavor is mildly nutty and slightly sweet — rich without being assertive.

Sharp white cheddar is added in smaller proportion for brightness and sharpness. Without it, a pure Gruyère gratin can taste flat and one-note. The white cheddar’s acidity provides contrast. Avoid yellow cheddar — the added coloring affects the appearance without improving flavor, and yellow cheddar can turn greasy at oven temperatures.

Both cheeses should be shredded fresh from the block. Pre-shredded cheese is coated with anti-caking agents (usually potato starch or cellulose) that prevent the cheese from melting into a smooth, fluid layer. A box grater takes three minutes and produces a noticeably better result.

Ruth’s Chris serves nearly every dish on a 500°F sizzling plate or cast-iron skillet — it’s the restaurant’s defining table-side experience. For potatoes au gratin, replicating this at home:

Method 1 (finish in cast iron): Bake the gratin in a standard baking dish for the full time. While it rests, heat 6-inch cast-iron skillets in a 400°F oven for 20 minutes. Portion the finished gratin into the hot skillets — the cold gratin hitting the hot iron sizzles on contact. Serve immediately.

Method 2 (bake in cast iron): Build and bake the gratin directly in two 6-inch cast-iron skillets. Cover with foil and bake at 350°F for 35 minutes, uncover and bake 15 to 20 minutes until golden. The thinner layer in individual skillets may finish 10 minutes earlier than a full casserole — test with a knife at the 25-minute uncovered mark.

Potatoes au gratin is one of the most reliable make-ahead Thanksgiving sides because it holds well at two different stages:

Assembled, unbaked: Layer the potatoes, cream, and cheese in the dish; cover with plastic wrap and refrigerate up to 2 days. Remove 30 minutes before baking to take the chill off, then bake as directed, adding 5 minutes to the covered stage if the dish is still cold. This method produces the best cheese crust.

Fully baked and reheated: Bake completely, cool to room temperature, cover with foil, and refrigerate up to 3 days. Reheat covered at 325°F for 20 minutes, then uncover for 8 to 10 minutes to re-brown the surface. The reheated crust will be slightly less golden than fresh-baked — the cheese absorbs ambient moisture in the refrigerator — but the flavor and texture are intact.

For a Thanksgiving table where oven space is at a premium, option 2 (fully baked) is the better logistics choice: it requires only reheating time on the day, and the quality difference is minor.

	Ruth’s Chris	Homemade
Presentation	Individual sizzling cast-iron skillet	Shared casserole or individual skillet
Price	$14–$17 per side	~$2.25 per serving
Cheese	Gruyère + white cheddar	Gruyère + white cheddar (matching)
Cream infusion	Pre-infused with garlic and thyme	Pre-infused (this recipe)
Potato variety	Yukon Gold	Yukon Gold (this recipe)

The dish is not difficult to replicate at home — the ingredients are supermarket staples and the technique is straightforward. Most home versions fall short because of two avoidable choices: using Russets instead of Yukons, and skipping the cream infusion step. Both are easy to get right.

Serving this alongside the Ruth’s Chris Filet Mignon and creamed spinach builds the full steakhouse plate; pairing it with a Gordon Ramsay-style roast turkey and the Ruth’s Chris sweet potato casserole covers the holiday table — all at a fraction of the restaurant cost.