Lemon Blueberry Sourdough Toast

There's something about a Sunday morning when the kitchen fills with the smell of butter and lemon that makes everything feel possible. I stumbled onto this recipe quite by accident—I had leftover sourdough, a container of blueberries threatening to go bad, and a sudden craving for something warm and custardy. The result was so unexpectedly brilliant that I've made it for nearly every special breakfast since, and it's become the one dish people actually request.

I made this for my sister's birthday breakfast last June, and she sat at the kitchen table with a forkful halfway to her mouth, just staring at it like it had personally offended her with how good it tasted. She asked for the recipe three times during that meal alone, and now I'm pretty sure she's made it more often than I have. That's when I knew this wasn't just a good recipe—it was the kind that gets passed around and becomes someone else's favorite thing.

Ingredients

• Sourdough bread (1 loaf, about 14 oz): Cut into 1-inch cubes and let them sit out for a few hours if possible so they're slightly stale—this matters more than you'd think, because stale bread holds the custard without turning to mush.
• Fresh or frozen blueberries (1 ½ cups): Frozen works just as well and sometimes better since they don't bleed as much; scatter them evenly or they'll all sink to the bottom.
• Lemon zest (from 1 lemon): Use a microplane if you have one, and don't skip this—the zest brings a brightness the juice alone can't capture.
• Large eggs (6): Room temperature if you can manage it, though honestly I've never bothered and it still turns out.
• Whole milk (2 cups): This is your custard base, so don't get creative with skim—the fat matters here.
• Heavy cream (½ cup): This is what makes it feel indulgent without being heavy; it's the difference between good and unforgettable.
• Granulated sugar (⅓ cup for custard, 2 tbsp for topping): The first amount sweetens the custard, and the second creates that crackly cinnamon-sugar crust that catches in your teeth.
• Pure vanilla extract (2 tsp): Seriously, use the real stuff here—imitation has a harshness that shows up in custards.
• Salt (¼ tsp): It balances everything and makes the lemon pop in unexpected ways.
• Lemon juice (from 1 lemon): Fresh squeezed, obviously—bottled just tastes sad in something this delicate.
• Unsalted butter, melted (2 tbsp): This drizzle before baking is what gets you that golden-brown top.
• Ground cinnamon (½ tsp): Mix this with the topping sugar and don't be shy with it.

Instructions

Set up your stage:

Grease a 9x13-inch baking dish with butter or cooking spray, then arrange your sourdough cubes so they're spread out evenly—not packed tight, not too loose. Scatter the blueberries over the bread like you're tucking them in, then sprinkle the lemon zest on top so every bite has a chance of catching some brightness.

Make the custard magic:

Crack your eggs into a large bowl and whisk them until they're pale and slightly frothy, then add milk, cream, sugar, vanilla, salt, and lemon juice. Whisk everything together until it's completely smooth and unified—about a minute of real whisking, not just a few lazy circles.

Soak the bread:

Pour the custard over the bread and berries, then take a fork and gently press down so the bread is submerged and starts absorbing all that eggy goodness. You want the liquid to reach the bottom of the dish so nothing stays dry, but be gentle or you'll turn your bread into paste.

Let time do the work:

Cover the dish with plastic wrap or foil and put it in the fridge for at least 30 minutes—or better yet, overnight. The bread keeps soaking up custard, and everything gets more cohesive and custardy the longer it sits.

Get ready to bake:

Preheat your oven to 350°F and remove the dish from the fridge about 10 minutes before baking so it's not ice-cold inside. Drizzle the melted butter over the surface, then mix your 2 tablespoons sugar with the cinnamon and sprinkle it all over the top—this becomes your crispy, caramelized crust.

Bake until golden:

Put it in the oven uncovered and let it bake for 45 minutes until the center jiggles just slightly when you shake the dish, and the top is golden brown and smells absolutely incredible. You'll know it's done when the edges are set but the very center still has the tiniest wobble—it'll firm up as it cools.

Rest and serve:

Let it cool for 10 minutes before cutting into it, because it needs that time to set properly and hold its shape. Serve it warm with maple syrup, a dust of powdered sugar, or just as is if you want to taste the custard and lemon without any interference.

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My neighbor tasted this once when I brought her over a portion on a random Thursday, and she started crying—not dramatically, just quiet tears because it tasted like comfort and effort and someone cared enough to make it for her. That's the moment I realized this recipe was about more than breakfast; it was about showing up for people with something warm and thoughtful.

Why Sourdough Matters Here

Regular sandwich bread would turn into wallpaper paste within minutes of hitting the custard, but sourdough has this magical structure that holds firm while still soaking up every drop of flavor. The slight tang in sourdough also plays beautifully with the lemon and blueberries—it adds complexity that makes people pause mid-bite and wonder what exactly just happened on their tongue. I learned this through trial and error, mostly error, but now I'm evangelical about it.

The Lemon-Blueberry Balance

Getting the citrus-to-berry ratio right took me several attempts because I kept being shy with the lemon, thinking it might be too much. Once I committed to the full amount of juice and zest, everything clicked—the brightness cuts through the richness of the custard and makes the blueberries taste even more like themselves. The key is using both zest and juice because they do different things; the zest gives you little bursts of lemon flavor throughout, while the juice provides an overall tang.

Make-Ahead Magic and Variations

This is genuinely one of the best make-ahead breakfasts because you do all the work the night before and just pop it in the oven while you're still in your pajamas. I've made it with raspberries when blueberries weren't available, and it was equally beautiful—the tartness of raspberries actually brought out the lemon even more. You can also use any bread that's slightly stale and sturdy enough to hold up: challah, brioche, even thick-cut French bread works if you're desperate.

• Try adding a teaspoon of lemon extract along with the juice for even more intensity without making it sour.
• A splash of Cointreau or Grand Marnier added to the custard transforms it into something you'd serve at a fancy brunch.
• Make it dairy-free by swapping the milk and cream for unsweetened oat milk and coconut cream, though the texture will be slightly less custardy.

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This breakfast casserole has become my go-to when I want to do something kind through food, and it never fails to make people feel cared for. Make it, serve it warm, and watch what happens when people taste something that clearly took thought.