Creamy Potato, Mushroom, and Brie Bake with Caramelized Onions
A luxuriously rich, soul-warming casserole that brings together velvety potatoes, deeply savory mushrooms, indulgent Brie, and sweet, golden caramelized onions—this Creamy Potato, Mushroom, and Brie Bake is comfort food elevated to elegant simplicity.
Why this dish is simply irresistible
- Decadent flavor layers: buttery potatoes + rich Brie + sweet caramelized onions.
- Perfect texture: tender potatoes, silky cream, and golden edges.
- Crowd-pleasing: elegant enough for holidays, cozy enough for weeknights.
Ingredients (and why they matter)
- 2 teaspoons vegetable oil — helps crisp the bacon and prevents sticking.
- 10 ounces turkey bacon, chopped — smoky savory layer with lighter richness than pork bacon.
- 1 large onion, thinly sliced — caramelizes into sweet strands that balance the cream.
- 1 cup mushrooms, thinly sliced — adds earthy savor that complements Brie.
- 1 teaspoon fresh thyme leaves, chopped — aromatic herb to lift the richness.
- 1 garlic clove, minced — aromatic boost for savory depth.
- 2 cups heavy cream — creates the luxurious, silky sauce.
- 1¼ cups whole milk — lightens the cream slightly for the perfect texture.
- 2 pounds waxy potatoes, peeled and thinly sliced — hold their shape and absorb flavor without falling apart.
- 9 ounces Brie cheese, sliced — the star: melts into buttery, gooey pockets.
- Freshly ground black pepper, to taste — balances the rich creaminess.
Step-by-step instructions
- Preheat the oven: Set to 375°F (190°C). Grease a 9×13-inch baking dish. (This ensures even baking and easy serving.)
- Crisp the turkey bacon: In a large skillet over medium heat, warm the vegetable oil and cook the chopped turkey bacon until crisp. Remove bacon and set aside — leave drippings in the skillet for flavor.
- Caramelize the onions: Add the sliced onion to the skillet and cook on low, stirring occasionally, until deep golden and sweet (~15–20 minutes). This step builds crucial sweet-savory complexity.
- Add mushrooms, thyme & garlic: Stir in mushrooms, thyme, and minced garlic; cook 4–5 minutes until mushrooms are tender and fragrant.
- Mix the cream base: In a bowl, whisk together 2 cups heavy cream, 1¼ cups whole milk, and freshly ground black pepper. This will bathe the potatoes and make the casserole silky.
- Layer the bake: In the prepared dish layer as follows:
- Half the potatoes (arrange in even overlapping rows)
- Half the cooked bacon
- Half the onion–mushroom mixture
- Half the sliced Brie
- Pour the cream: Evenly pour the cream mixture over the layers, pressing gently so the liquid settles between potato slices.
- Bake covered: Cover with foil and bake for 45 minutes. Remove foil and bake another 15–20 minutes until potatoes are tender and top is golden and bubbly.
- Rest & finish: Let cool a few minutes, garnish with extra fresh thyme, slice, and serve warm.
Pro tips for perfect results
- Mandoline for even slices: Use a mandoline to slice potatoes uniformly (about 1/8″–3/16″ thick) so layers cook evenly.
- Patience with onions: Fully caramelize onions — that deep sweetness transforms the dish.
- Keep the Brie rind: The rind melts and adds complexity; remove it only if you prefer a milder finish.
- Short rest before serving: Let the casserole sit 5–10 minutes so it firms up and slices neatly.
Serving suggestions
This Creamy Potato, Mushroom, and Brie Bake pairs beautifully with:
- Roast chicken or turkey for a hearty, balanced meal.
- A crisp green salad with citrus vinaigrette to cut the richness.
- Steamed green beans or asparagus for freshness.
- A crusty baguette to sop up the luscious cream sauce.
Vegetarian option: Omit the turkey bacon or substitute plant-based bacon for a vegetarian-friendly main.
Quick nutrition & timings
Approx: 350 kcal per serving • Prep 15 min • Bake 1 hr • Serves 8
