Classic Rhubarb Crisp with Frozen Rhubarb

There’s something wonderful about finding frozen rhubarb in the back of your freezer when you’re craving a taste of spring. I’ve learned that frozen rhubarb works just as well as fresh in most recipes, and this crisp is proof of that. When my kids were little, they’d wrinkle their noses at rhubarb, but this recipe changed everything – now it’s a family favorite.

Making a rhubarb crisp with frozen rhubarb is actually easier than using fresh. No cleaning or chopping required – just thaw, drain, and you’re ready to go. I often make this dessert in winter when we need something cozy and warm, and the tart-sweet combo brings back memories of warmer days. Plus, the buttery crumble topping makes the whole house smell amazing while it bakes.

What Kind of Rhubarb Should I Use?

Both fresh and frozen rhubarb work great in this crisp, so you can make it year-round. Fresh rhubarb stalks should be firm and crisp, with a bright pink to red color – though the green parts are perfectly fine to use too. If you’re using frozen rhubarb, there’s no need to thaw it first; just add it straight to your recipe while it’s still frozen. Keep in mind that frozen rhubarb might release a bit more liquid as it bakes, but the cornstarch in the recipe will help thicken things up nicely. When buying fresh rhubarb, look for stalks that are about 1 to 2 inches wide, as these tend to be more tender and less stringy than the really thick ones.

Options for Substitutions

This cozy rhubarb crisp recipe can be tweaked in several ways if you need to make substitutions:

• Rhubarb: While rhubarb gives this dessert its classic tangy taste, you can mix it with strawberries (use half rhubarb, half strawberries) or replace it completely with tart apples or fresh cranberries. Just keep the total amount of fruit the same.
• Cornstarch: Out of cornstarch? Use all-purpose flour instead – you’ll need about 1/2 cup since flour isn’t as strong of a thickener as cornstarch. Tapioca starch works too, but use just 3 tablespoons.
• Oats: Both quick oats and old-fashioned work here. If you’re out of oats, try using chopped nuts (like almonds or pecans) mixed with extra flour for a different but equally tasty topping.
• Butter: For a dairy-free version, solid coconut oil works great. Just make sure it’s cold when you cut it in. Vegan butter alternatives also work well here.
• Sugar: Feel free to use brown sugar instead of white in the topping – it adds a nice caramel note. For the filling, stick with regular sugar to let the rhubarb shine through.

Watch Out for These Mistakes While Baking

The biggest challenge when using frozen rhubarb is managing its water content – make sure to thaw it completely in a colander and drain well, otherwise you’ll end up with a soupy dessert instead of a crisp. A common error is skipping the cornstarch, but it’s essential for thickening all those natural juices that rhubarb releases while baking. For the topping, avoid using warm or room-temperature butter – cold butter is crucial for achieving that perfect crumbly texture, so keep it chilled until the moment you’re ready to mix it into the dry ingredients. Another mistake is pulling the crisp out too early; wait until you see the filling bubbling around the edges and the topping turns golden brown, which usually takes about 45-50 minutes. Let the crisp cool for at least 20 minutes before serving – this resting time allows the filling to set properly and prevents a runny mess when you scoop it out.

What to Serve With Rhubarb Crisp?

This tart and sweet dessert practically begs for something creamy to go alongside it! A scoop of vanilla ice cream is the classic choice – it melts perfectly into the warm crisp and creates an amazing contrast of temperatures. If you’re not in the mood for ice cream, a dollop of freshly whipped cream or even a pour of cold heavy cream works beautifully too. For brunch settings, I love serving rhubarb crisp with a cup of hot coffee or tea, which helps balance out the dessert’s natural tartness. You could also add a sprinkle of chopped nuts on top for extra crunch if you’re feeling fancy!

Storage Instructions

Keep Fresh: Once your rhubarb crisp has cooled down, cover it with plastic wrap or transfer it to an airtight container. It’ll stay good in the fridge for up to 5 days. The topping might lose some of its crunch over time, but it’ll still taste great!

Freeze: This crisp freezes really well! Let it cool completely, then wrap it tightly in plastic wrap and aluminum foil, or place it in a freezer-safe container. It’ll keep for up to 3 months in the freezer. You can freeze it either baked or unbaked – both work great!

Warm Up: To enjoy your refrigerated crisp, pop it in a 350°F oven for about 15-20 minutes until it’s heated through. If you’re working with a frozen crisp, thaw it overnight in the fridge first, then warm it up the same way. A quick zap in the microwave works too, though the topping won’t be as crispy.

Preparation Time	15-20 minutes
Cooking Time	35-40 minutes
Total Time	50-60 minutes
Level of Difficulty	Easy

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 1800-2000
• Protein: 12-15 g
• Fat: 80-90 g
• Carbohydrates: 250-280 g

Ingredients

For the filling:

• 2 lb rhubarb (frozen, cut into 1-inch pieces)
• 1/2 tsp cinnamon (for warm spice notes)
• 3/4 cup sugar
• 1/4 cup cornstarch (to thicken the filling)

For the topping:

• 1/2 tsp cinnamon
• 1 stick cold butter (unsalted, cut into small cubes)
• 1/2 cup flour (all-purpose flour)
• 1 cup oats (old-fashioned rolled oats for best texture)
• 1/2 cup sugar
• 1 pinch salt

Step 1: Prepare the Oven and Casserole Dish

Begin by preheating your oven to 400°F (200°C).

While the oven is heating, lightly butter a roughly 2-quart casserole dish to prevent sticking.

Step 2: Make the Rhubarb Filling

In a large bowl, combine all the ingredients for the rhubarb filling.

Mix well to ensure the rhubarb is evenly coated.

Once combined, spread the rhubarb filling evenly in the prepared casserole dish to create the base of the crisp.

Step 3: Prepare the Topping

In another large bowl, combine oats, flour, sugar, cinnamon, and a pinch of salt.

Mix these dry ingredients to distribute evenly.

Cut in the butter using a pastry cutter or your fingers until the mixture forms crumbs.

This will be your crumb topping.

Step 4: Assemble and Bake

Evenly scatter the crumb topping over the rhubarb filling in the casserole dish.

Place the dish in the preheated oven and bake for about 35 minutes.

The crisp is ready when the topping is golden and the filling is bubbly.

Step 5: Allow to Cool and Serve

Once baked, remove the rhubarb crisp from the oven.

Allow it to sit on the counter for at least 10 minutes to cool slightly and set.

Serve warm and enjoy the delicious contrast of tart rhubarb and sweet, crunchy topping.