Mushroom and Gruyère Breakfast Bread Pudding Bake

Name: Mushroom and Gruyère Breakfast Bread Pudding Bake
Prep time: 25 min
Cook time: 45 min
Total time: 1 h 10 min
Yield: 6 servings
Cuisine: French
Ingredients: 10 oz (280 g) crusty bread (such as ciabatta or sourdough), cut into 1-inch cubes; 12 oz (340 g) cremini or baby belella mushrooms, cleaned with damp paper towel, trimmed, sliced ½-inch thick; 2 whole (80 g) medium shallots, thinly sliced; 3 tablespoons (43 g) unsalted butter, room temperature; 4 sprigs (5 g) fresh thyme sprigs, leaves stripped from stems; 5 oz (140 g) Gruyère cheese, aged 6+ months, finely grated; 6 whole (300 g) large eggs, at room temperature; 1½ cups (360 ml) heavy cream, room temperature; ½ cup (120 ml) whole milk, room temperature; 1 teaspoon (5 ml) Dijon mustard; ¼ teaspoon (½ g) freshly grated nutmeg; fine sea salt, to taste; freshly ground black pepper, to taste

From the MyKitchenBank Kitchen

A sophisticated savory bread pudding infused with sautéed mushrooms, sharp Gruyère cheese, and fresh thyme. Cubed crusty bread absorbs a custard of eggs and cream, creating a creamy interior with golden edges. Perfect for brunch entertaining—assemble the night before and bake in the morning.

Prep: 25 min
Cook: 45 min
Wait: 8 hr 30 min
Total: 9 hr 40 min
Makes: One 9×13-inch (23×33 cm) bake, 6 generous servings

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Ingredients

6 servings

10 oz (280 g) crusty bread (such as ciabatta or sourdough), cut into 1-inch cubes
12 oz (340 g) cremini or baby belella mushrooms, cleaned with damp paper towel, trimmed, sliced ½-inch thick
2 whole (80 g) medium shallots, thinly sliced
3 tablespoons (43 g) unsalted butter, room temperature
4 sprigs (5 g) fresh thyme sprigs, leaves stripped from stems
5 oz (140 g) Gruyère cheese, aged 6+ months, finely grated
6 whole (300 g) large eggs, at room temperature
1½ cups (360 ml) heavy cream, room temperature
½ cup (120 ml) whole milk, room temperature
1 teaspoon (5 ml) Dijon mustard
¼ teaspoon (0.5 g) freshly grated nutmeg
fine sea salt, to taste
freshly ground black pepper, to taste

Equipment (8)

9×13-inch (23×33 cm) baking dish, buttered
Large skillet
Small saucepan
Cutting board and chef's knife
Measuring cups and spoons
Large mixing bowl
Whisk
Cheese grater

Steps

Before you start

Remove eggs and cream from the refrigerator 30 minutes before baking so they reach room temperature
Preheat the oven to 375°F (190°C) about 15 minutes before baking
If assembling the day ahead, cover the baking dish tightly with plastic wrap and refrigerate overnight; add 10 minutes to baking time

1
Sauté mushrooms and shallots
- Heat the butter in a large skillet over medium-high heat (about 2 minutes).
- Add the sliced mushrooms and shallots; cook, stirring occasionally, for 8–10 minutes until the mushrooms have released their liquid and the mixture is golden and nearly dry.
- Add the thyme leaves in the last minute of cooking.
- Season with salt and pepper to taste.
- Transfer to a plate and let cool for 5 minutes.
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Ready when: Mushrooms are golden and most liquid has evaporated
Tip: Don't overcrowd the pan; cook mushrooms in a single layer so they brown rather than steam.
2
Prepare the bread and baking dishOven 375°F / 190°C
- Cut the crusty bread into 1-inch cubes (you should have about 6 cups).
- Spread the cubes on a baking sheet and toast in a 375°F (190°C) oven for 5 minutes just to dry them slightly—this prevents them from becoming mushy.
- Spread the toasted bread in a buttered 9×13-inch (23×33 cm) baking dish.
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Ready when: Bread is dry to the touch, pale and toasted
Tip: If your bread is already day-old and quite dry, skip the toasting step to avoid over-drying.
3
Layer mushrooms and cheese
- Scatter the cooled mushroom and shallot mixture evenly over the bread cubes.
- Sprinkle 3½ ounces (100 g) of the grated Gruyère evenly over the mushrooms, reserving the remaining 1½ ounces (40 g) for the top layer.
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Tip: Reserve some cheese for the top so it gets extra crispy and golden.
4
Whisk custard mixture
- In a large bowl, whisk together the 6 eggs, heavy cream, whole milk, Dijon mustard, and nutmeg until smooth and fully combined.
- Season with salt and pepper to taste.
- The custard should be pale and homogeneous.
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Ready when: Custard is smooth with no visible egg white streaks
Tip: Use room-temperature eggs and cream to ensure a smooth, lump-free custard.
5
Pour custard and set overnight (or 1 hour)
- Pour the custard evenly over the bread and mushroom layers in the baking dish, making sure it soaks into all the bread.
- Sprinkle the reserved 1½ ounces (40 g) of Gruyère over the top.
- Cover the baking dish with plastic wrap and refrigerate for at least 1 hour (ideally overnight) so the bread fully absorbs the custard.
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Ready when: Bread is saturated and custard is evenly distributed
Tip: Don't skip the soaking step—it ensures the bread absorbs the custard and bakes evenly instead of drying out on top.
6
Bake until golden and setOven 375°F / 190°C
- Preheat the oven to 375°F (190°C).
- Remove the baking dish from the refrigerator; if it came straight from overnight storage, let it sit at room temperature for 15 minutes.
- Remove the plastic wrap and bake uncovered for 40–45 minutes until the top is deep golden brown and the center is just set but still slightly jiggly in the very middle.
- A knife inserted ¾-inch from the edge should come out clean; the absolute center may be slightly soft, which will firm up as it rests.
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Ready when: Top is deep golden brown; edges are slightly puffed; center is set but still has slight give
Tip: Don't overbake or the custard will toughen. It should be creamy, not firm throughout—residual heat will continue cooking as it rests.
7
Rest before serving
- Remove the bread pudding from the oven and let it rest on the counter for 10 minutes.
- This allows the custard to set further and makes serving easier without the pudding falling apart.
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Ready when: Pudding is warm and has firmed up slightly
Tip: A 10-minute rest is crucial—it prevents the pudding from collapsing when you cut and serve it.

Good to know

Tips

For extra moisture, add 2 tablespoons of dry white wine or sherry to the mushroom sauté in Step 1 (let it reduce to a few tablespoons before adding the thyme)
If the top browns too quickly before the custard sets, tent loosely with foil for the final 10 minutes of baking
Pair with a simple green salad tossed with a light vinaigrette and serve with crusty bread on the side to soak up any extra custard
Make this vegetarian-friendly by simply omitting any meat and using vegetable stock to wet the sauté pan if needed

Make ahead

Assemble the entire dish through Step 5 (before baking). Cover and refrigerate overnight up to 16 hours. In the morning, remove from the refrigerator 15 minutes before baking, then proceed with Step 6. Do not freeze; the custard doesn't refreeze well.

Storage & reheating

Refrigerate leftovers in an airtight container for up to 3 days. To reheat, cover loosely with foil and warm in a 300°F (150°C) oven for 15 minutes until just heated through. Do not reheat in the microwave, as it will make the custard rubbery. Not suitable for freezing due to custard texture changes.

Substitutions

Gruyère cheese, aged 6+ months → Aged cheddar (sharp or extra-sharp) or Emmental cheese. Use the same weight. Both melt well and provide similar nutty depth. Gruyère is preferred for its complexity, but cheddar works if you prefer a sharper flavor.
cremini or baby belella mushrooms → Cremini, oyster, or a mix of wild mushrooms (chanterelles, porcini, shiitake). Use the same weight. Cremini is the mildest; oyster and wild varieties add deeper earthiness. Avoid button mushrooms—they're too watery.
heavy cream → Half heavy cream and half whole milk (¾ cup cream + ¾ cup milk). Creates a lighter custard with less richness. The pudding will be slightly less creamy but still excellent.
crusty bread (such as ciabatta or sourdough) → Day-old brioche or challah cut into cubes. Creates a richer, slightly sweet contrast to the savory filling. Use the same weight.