Au Gratin Potatoes with Fennel and California Ripe Olives

This Au Gratin Potato Recipe is creamy, cheesy and full of flavor thanks to sliced fennel and sliced black olives. It makes a perfect side for Thanksgiving or any holiday table and pairs beautifully with turkey or ham.

This post was created in partnership with California Ripe Olives. All opinions are my own.

Even though it’s only September, I’m already thinking about fall and planning my Thanksgiving menu. Creamy, cheesy potatoes show up on our holiday table nearly every year—sometimes as a sweet potato gratin, sometimes as funeral potatoes—but a comforting au gratin is always welcome. When California Ripe Olives asked me to develop a Thanksgiving side featuring olives, Potatoes Au Gratin was an obvious choice.

This version uses russet potatoes layered with thinly sliced fennel and onion. Fennel brings a subtle, bright anise-like note that lifts the dish and makes it stand out from standard gratins. For the cheese, I combine nutty Gruyere and smooth Jarlsberg; both are mild Swiss-style cheeses that melt into a rich, savory cream without overwhelming the other ingredients.

Heavy cream is the cooking liquid here: it keeps the vegetables moist while baking and reduces into a silky sauce as it cools. The recipe looks elegant but is straightforward—most of the work is slicing the vegetables.

I have fond memories of holiday tables at my grandparents’ house: bowls of baby gherkin pickles and black olives were always present. As a child I would sneak olives from the platter and enjoy them in secret. Today I still enjoy olives in many ways—straight from the jar, on a vegetable platter, or folded into a warm gratin for added texture and briny depth. California Ripe Olives are a reliable pantry staple for this reason.

How To Make Easy Potato Au Gratin with California Ripe Olives

1. Prep and thinly slice fennel, onion, and potatoes. A mandoline or handheld slicer gives uniform slices that cook evenly; aim for slices just under 1/8 inch if possible.
2. Sauté the onion and fennel in olive oil (and a bit of butter, if desired) over medium-low heat until very tender and beginning to caramelize, about 15 minutes. This develops sweetness and softens the vegetables.
3. In a large bowl, combine the sliced potatoes and olives with the heavy whipping cream, salt, pepper, and all but a few tablespoons of the grated cheeses. Stir in the cooked fennel and onion.
4. Transfer the mixture to an 8×8-inch baking dish or deep pie plate, pressing to level and ensuring the potatoes are mostly submerged in the cream.
5. Mix the remaining cheese with a couple of tablespoons of cream and sprinkle evenly over the top of the casserole.
6. Bake at 350°F (175°C) for 45–60 minutes, or until the potatoes are very tender and the top is golden and bubbly. Test doneness by inserting a fork into the center—if there’s resistance, continue baking. Tent with foil if the top browns too quickly.
7. Let cool at least 15 minutes before serving so the sauce sets and the dish slices cleanly.

Tips for Perfect Au Gratin Potatoes

• Use a mandoline or handheld slicer: Uniform slices cook more evenly and give a polished finished look.
• Use heavy whipping cream: Heavy cream (about 36% milkfat) yields the richest, creamiest sauce. Lighter creams won’t give the same silky texture.
• Choose the right cheese: Any good melting cheese will work, but Gruyere and Jarlsberg balance nuttiness and creaminess without overpowering the dish.
• Check for tenderness: The gratin is done when a fork or sharp knife slides easily through the potatoes in the center. If needed, continue baking and tent with foil to prevent over-browning.
• Pick ripe olives from California: California Ripe Olives undergo a consistent curing process and add a dependable, briny note. Use sliced olives so they distribute evenly through the gratin.

What does Au Gratin Mean?

Au gratin refers to a dish topped with cheese and/or breadcrumbs and browned until bubbly and golden.

Au Gratin Potatoes vs. Scalloped Potatoes

Traditionally, scalloped potatoes are baked in a creamy sauce without cheese, while au gratin includes cheese on top. In modern usage the terms are often used interchangeably, but the presence of cheese is the main distinction.

What Goes Well With Au Gratin Potatoes?

This mild, creamy side dish complements many proteins. Try it with roasted or brined turkey, baked ham, classic meatloaf, roasted pork, oven-baked BBQ chicken, or grilled chicken.

📖 Recipe

Easy Au Gratin Potato Recipe with Fennel and California Ripe Olives

These potatoes are easy: just slice, sauté, mix, and bake for creamy, cheesy comfort.

By Heather Cheney

Prep Time: 15 minutes

Cook Time: 1 hour

Servings: 6 servings

Ingredients

• 1 bulb fennel, washed, stalks removed and cored
• 1/2 whole yellow onion
• 2 large russet potatoes, washed and peeled
• 1 tablespoon olive oil
• 1 tablespoon salted butter
• 1 cup plus 2 tablespoons heavy whipping cream, divided
• 3/4 cup Gruyere cheese, grated, divided
• 3/4 cup Jarlsberg cheese, grated, divided
• 1/2 cup California Ripe Olives, sliced
• 1/2 teaspoon kosher salt
• 1/8 teaspoon black pepper

Instructions

1. Preheat oven to 350°F (175°C).
2. Thinly slice fennel, onion, and potatoes with a mandoline or handheld slicer; adjust cooking time if slices are thicker.
3. In a medium pan, heat butter and olive oil and sauté onion and fennel over medium-low heat for about 15 minutes, until very tender. Remove from heat.
4. In a large bowl, combine the sliced potatoes with 1 cup plus 2 tablespoons cream, the sliced olives, salt, pepper, and all but 2 tablespoons of each cheese.
5. Stir the cooked fennel and onion into the potato mixture, then transfer to an 8×8-inch baking dish, pressing so the potatoes are mostly submerged in the cream.
6. Mix the remaining 2 tablespoons of each cheese with 2 tablespoons cream and sprinkle evenly over the top.
7. Bake 45–60 minutes, until potatoes are tender and the top is golden and bubbly. Tent with foil if the top browns too quickly.
8. Let rest at least 15 minutes before serving so the sauce sets.

Chef’s Notes:

• Mandoline or slicer: Uniform slices ensure even cooking and a tidy presentation.
• Use heavy whipping cream: It creates the richest sauce; lighter creams will change the texture.
• Cheese choices: Gruyere and Jarlsberg melt well and balance each other; substitute similar melting cheeses if needed.
• Check for tenderness: The gratin is done when a fork slides easily into the center. Continue baking if you feel resistance.

Nutrition Facts

Serving: 1 serving | Calories: 418 kcal

Useful Tools For This Recipe

Mandoline Slicer

8×8″ Baking Dish

Nutrition and Food Safety Disclosure

More Potato Recipes You Might Like

• Baked Sweet Potatoes
• Steakhouse Potatoes
• Grilled Sweet Potatoes
• Slow Cooker Mashed Potatoes
• Oven Roasted Potatoes

Other Recipes For Your Thanksgiving Dinner Menu

• Sweet Potato Casserole With Coconut
• Corn Spoon Bread
• Best Dinner Roll Recipe
• Fresh Green Bean Casserole
• Homemade Creamed Corn
• Cranberry Fluff
• Pumpkin Turnovers
• Never Fail Pie Crust
• Caramel Apple Pie with Crumb Topping