Name: Vegetarian Mushroom and Potato Bake Recipe
Prep time: 25 min
Cook time: 1 h
Total time: 1 h 40 min
Yield: 8
Cuisine: European
Ingredients: 700–800 g waxy potatoes, very thinly sliced (2–3 mm); 600–700 g cremini or chestnut mushrooms, thickly sliced; 2 tbsp olive oil; 30 g butter (or vegan butter); 1 large onion, very thinly sliced; 3–4 garlic cloves, minced; 2 tsp fresh thyme leaves (or 1 tsp dried); 40 g plain flour; 600 ml milk (dairy or unsweetened plant milk); ½ tsp ground nutmeg (optional); 80–100 g freshly grated Parmesan (or 5–6 tbsp nutritional yeast + 1 tsp white miso for vegan); Salt & freshly ground black pepper, to taste; Optional topping: extra Parmesan/nutritional yeast + a handful of panko breadcrumbs mixed with 1 tsp olive oil

This comforting Vegetarian Mushroom and Potato Bake layers thinly sliced potatoes with golden sautéed mushrooms, caramelized onions, fresh thyme, garlic, and a creamy béchamel-style sauce, then bakes until bubbling and golden on top. Finished with a sprinkle of Parmesan (or nutritional yeast), it’s a cozy, hearty vegetarian main or side dish full of earthy flavour.

Why You’ll Love This Recipe

You’ll adore this Vegetarian Mushroom and Potato Bake because it delivers all the cosy, soul-warming satisfaction of a classic gratin or shepherd’s pie—without any meat. The mushrooms bring deep savoury umami and meaty texture, the potatoes become meltingly tender inside with crisp golden edges, and the creamy sauce ties everything together into pure comfort.

It’s naturally adaptable (easy vegan version), uses mostly pantry staples plus two fresh ingredients, feels special enough for Sunday lunch or guests, yet is simple enough for weeknight cooking.

The house smells incredible while it bakes, it reheats beautifully, freezes well, and is filling, nourishing, and universally loved—even by dedicated meat-eaters. Once you taste that first forkful of creamy, garlicky, thyme-scented goodness, it quickly becomes one of those reliable recipes you turn to whenever you want something hearty, homemade, and deeply satisfying.

Yield: 8 servings

Vegetarian Mushroom and Potato Bake Recipe

Creamy vegetarian mushroom-potato bake—golden, comforting, earthy, and perfect for family dinners!

Prep Time 25 minutes

Cook Time 1 hour

Additional Time 15 minutes

Total Time 1 hour 40 minutes

Ingredients

700–800 g waxy potatoes, very thinly sliced (2–3 mm)
600–700 g cremini or chestnut mushrooms, thickly sliced
2 tbsp olive oil
30 g butter (or vegan butter)
1 large onion, very thinly sliced
3–4 garlic cloves, minced
2 tsp fresh thyme leaves (or 1 tsp dried)
40 g plain flour
600 ml milk (dairy or unsweetened plant milk)
½ tsp ground nutmeg (optional)
80–100 g freshly grated Parmesan (or 5–6 tbsp nutritional yeast + 1 tsp white miso for vegan)
Salt & freshly ground black pepper, to taste
Optional topping: extra Parmesan/nutritional yeast + a handful of panko breadcrumbs mixed with 1 tsp olive oil

Instructions

Preheat oven to 190°C (375°F) fan / 200°C conventional. Lightly grease a 23×33 cm (9×13 inch) baking dish.
Heat 1 tbsp olive oil and 15 g butter in a large skillet over medium-high heat.
Add sliced mushrooms in a single layer (batch if needed)—let sit undisturbed 3–4 minutes until deep golden, then stir and cook another 3–4 minutes until browned. Season with salt & pepper, remove to a plate.
In the same pan, add remaining 1 tbsp oil and 15 g butter. Add sliced onion—cook gently 8–10 minutes until soft and caramelized.
Stir in minced garlic and thyme—cook 60 seconds until fragrant.
Sprinkle flour over onions—stir 1–2 minutes to cook out raw taste.
Gradually pour in milk while whisking constantly to avoid lumps. Add nutmeg (if using), salt & pepper. Simmer gently 4–6 minutes until thickened to a coating consistency. Taste and adjust seasoning.
Remove sauce from heat. Stir in half the Parmesan/nutritional yeast mixture and all the cooked mushrooms.
Layer half the potato slices in the baking dish (slightly overlapping). Spread half the mushroom-cream mixture over potatoes. Repeat with remaining potatoes and sauce. Finish with remaining Parmesan/nutritional yeast and optional breadcrumb topping.
Cover with foil and bake 30 minutes. Uncover and bake another 20–30 minutes until potatoes are tender, top is golden, and edges are bubbling. Let rest 10–15 minutes before serving—slice into squares and enjoy this creamy, earthy vegetarian bake that tastes like pure comfort!

Notes

Slice potatoes as thinly and evenly as possible (mandoline helps) so they cook through. Brown the mushrooms properly—it’s the flavour foundation. Vegan version works beautifully with plant milk, vegan butter, and nutritional yeast + miso. Let it rest before cutting for clean slices.

Nutrition Information

Yield

Serving Size

1
Amount Per Serving Calories 100Total Fat 7gSaturated Fat 3gUnsaturated Fat 5gCholesterol 10mgSodium 40mgCarbohydrates 7gFiber 1gSugar 1gProtein 2g

The recipes and nutritional information on Yum Tonight are for informational purposes only. Always consult a healthcare provider for personalized dietary advice.

Recipe Tips and Tricks

Slice potatoes very thinly (mandoline is ideal) so they cook through evenly in the oven. Pat mushrooms dry before sautéing—they brown much better and develop deeper flavour. Caramelize the onions slowly for sweetness that balances the earthiness of mushrooms.

Let the béchamel thicken properly before assembling—too thin and the bake becomes watery. Cover with foil for the first half of baking so potatoes steam and soften; uncover later for golden top.

For extra crispiness, scatter a handful of panko or breadcrumbs mixed with a little oil and herbs on top during the last 10–15 minutes. Let the bake rest 10–15 minutes after baking—it sets up beautifully and slices cleanly. Taste the mushroom mixture before layering and adjust salt, pepper, and herbs generously.

Ingredients Notes

Cremini (baby bella) or chestnut mushrooms are perfect—firm, earthy, and widely available; they hold shape and develop rich colour when browned. Waxy potatoes (such as Nicola, Charlotte, or new potatoes) are best—they keep their shape and become tender without turning mushy.

Onion (yellow or brown) caramelizes for natural sweetness. Fresh garlic and thyme provide classic aromatic depth—fresh thyme makes a noticeable difference. Butter and flour create the base of a simple béchamel-style sauce; milk (dairy or unsweetened plant milk) gives creaminess.

Parmesan (or nutritional yeast + pinch miso for vegan) adds nutty, savoury punch. Extra-virgin olive oil for sautéing mushrooms; salt, black pepper, and optional nutmeg in the sauce for subtle warmth.

Variations and Substitutions

Make it vegan with plant-based butter, unsweetened oat/soy/almond milk, and nutritional yeast + a touch of white miso instead of Parmesan. Add spinach, kale, or Swiss chard between layers for extra greens. Include caramelized leeks, roasted garlic, or sun-dried tomatoes for deeper flavour.

For protein boost, mix in cooked green lentils, white beans, or crumbled tempeh with the mushrooms. Go lighter with half milk + half vegetable broth in the sauce. Add a layer of sliced zucchini or eggplant (lightly salted and patted dry first). Spice it up with smoked paprika, chili flakes, or a pinch of cayenne.

Use sweet potatoes instead of regular potatoes for a sweeter twist. Top with crushed garlic croutons or crispy onions in the last 10 minutes for texture contrast. Turn it into individual portions in ramekins (reduce bake time to 25–30 minutes).

Storage Options

Refrigerate leftovers tightly covered for up to 4 days. Reheat covered in a 170°C oven for 20–30 minutes or until piping hot (add a splash of milk if it looks dry); microwave individual portions with a damp paper towel over the top.

Freezes very well up to 3 months—cool completely, portion, wrap tightly; thaw overnight in the fridge and reheat covered in oven (add 10–15 minutes extra time if cold). The bake actually tastes even better the next day as flavours meld.