Lemon Blueberry Crumble Bars
Buttery crumble bars with a pressed shortbread base, a juicy blueberry and lemon layer, and a crumbly topping.
- Measurements grams + cups
- Cuisine American
Why You'll Like This Recipe
- The base and the topping are the same mixture, so there is one bowl and one set of measuring to do.
- Works with frozen blueberries straight from the freezer, which makes it a year-round bake.
- The lemon keeps it from being simply sweet — blueberry on its own can taste flat once baked.
Recipe
Lemon Blueberry Crumble Bars
Buttery crumble bars with juicy blueberries and bright lemon.
Ingredients
Ingredients scaled. The method below still refers to the original quantities.
For the crumble
For the filling
Instructions
Make the crumble
- Step 1. Heat the oven to 175 C / 350 F. Line a 20 x 20 cm / 8 x 8 inch pan with parchment, leaving an overhang on two sides.
- Step 2. Mix the flour, 80 g sugar and salt in a large bowl.
- Step 3. Cut in the cold butter with a pastry cutter or two knives until the mixture looks like coarse crumbs with some pea-sized pieces remaining.
- Step 4. Press about two-thirds of the crumbs firmly and evenly into the base of the pan.
Fill and bake
- Step 5. Toss the blueberries with the remaining 40 g sugar, the cornstarch, lemon zest, lemon juice and vanilla.
- Step 6. Spread the fruit over the pressed base in an even layer.
- Step 7. Scatter the remaining crumbs loosely over the top, leaving some gaps so steam can escape.
- Step 8. Bake for 38 to 43 minutes, until the topping is golden and the filling bubbles at the edges.
- Step 9. Cool completely in the pan before lifting out and cutting into 16 bars.
Notes
- Press the base firmly. A loosely packed base crumbles when you lift the bars out and the fruit layer slides off.
- Leave gaps in the top layer of crumbs. Fruit gives off steam, and a sealed lid of crumble traps it and turns the topping soft.
- Cool completely before cutting. The filling is molten at first and sets as it cools — cut warm and it runs.
- If the topping is browning faster than the filling is bubbling, lay a sheet of foil loosely over the pan for the last 10 minutes.
Lemon Blueberry Crumble Bars — Simple Table Recipes · https://simpletablerecipes.com/recipes/lemon-blueberry-crumble-bars/
Ingredient Notes
- Cold butter
- Cold is what makes crumbs. Softened butter blends into a paste and the topping bakes as one solid sheet rather than a crumble.
- Cornstarch
- Blueberries release a lot of liquid. The cornstarch thickens it into something sliceable instead of a puddle that soaks the base.
- Lemon zest
- The zest carries the aromatic oils and does more for the flavour than the juice. Grate only the yellow layer — the pith underneath is bitter.
- Frozen blueberries
- Use them frozen and do not thaw. Thawed berries collapse and release their liquid before the cornstarch has any chance to set it.
Equipment
- 20 x 20 cm / 8 x 8 inch baking pan
- Parchment paper
- Large mixing bowl
- Pastry cutter or two knives
- Fine grater or zester
Substitutions
- Blueberries
- Blackberries, raspberries or a mix work at the same weight. Raspberries are wetter, so add an extra 5 g of cornstarch.
- Lemon
- Lime gives a sharper, more floral result. Orange is softer and sweeter and pairs better with blackberries than blueberries.
- All-purpose flour
- A cup-for-cup gluten-free blend containing xanthan gum works in the crumble. The base may need an extra 2 to 3 minutes.
Storage & Freezing
Storing: Refrigerate in an airtight container for up to 4 days. The topping softens slightly in the fridge but the bars cut more cleanly cold.
Freezing: Freeze cut bars, separated by parchment, for up to 2 months. Thaw in the fridge, then warm in a low oven for a few minutes to crisp the topping.
Frequently Asked Questions
Can I use frozen blueberries?
Yes, and they work well. Add them frozen and toss with the sugar and cornstarch as usual. Thawing first releases the juice too early and gives a soggy base.
Why is the base soggy?
Too much liquid in the fruit layer, or the bars were cut before they had cooled. Make sure the cornstarch is tossed through evenly and let them cool completely in the pan.
Why did my crumble topping turn into a solid sheet?
The butter was too warm. It should be cold from the fridge and cut in until crumbly, not blended smooth. If the bowl gets warm while you work, chill it for 10 minutes.
Can I double this for a 9 x 13 pan?
Yes. Double everything, use a 23 x 33 cm / 9 x 13 inch pan and add about 5 minutes to the bake. Check that the centre is bubbling before taking it out.
How do I get clean slices?
Chill the cooled slab for an hour, then cut with a large sharp knife, pressing straight down and wiping the blade between cuts.
Can I use bottled lemon juice?
The juice matters less here than the zest, so bottled juice is a reasonable compromise. Skipping the zest, though, takes most of the lemon character out of the bar.
Did you make this?
Let other people know how it went. One tap, nothing to fill in.
Thanks — that helps.
