These lemon blueberry crumble bars are one of my favorite treats to make when blueberries are in season. They have a buttery base, a soft fruit layer, and a golden crumble on top.

The mix of sweet blueberries and bright lemon is really nice together. It keeps each bite fresh instead of being too heavy.

Every part of this recipe is dairy free, so I use vegan butter instead of regular butter. It works just as well and no one can really tell the difference.

If you or someone in your family cannot have dairy, this is a good dessert to keep in mind. It feels special but is still simple to put together.

Let me show you how I make these bars step by step.

Why This Recipe Is a Keeper

Bright Lemon and Blueberry Flavor – The fresh lemon zest and juicy blueberries mix into a sweet and tangy filling that tastes like summer in every bite.

Perfect Crumbly Texture – The buttery oat crust stays firm on the bottom while the golden crumble on top adds a lovely soft crunch.

Fully Dairy Free – Made with vegan butter, these bars taste rich and buttery without any dairy at all.

Simple to Make – You just mix, press, layer, and bake, so even beginners can pull these off with ease.

Here’s What You’ll Need

For The Crust And Crumble

2 cups All-Purpose Flour
1/2 cup Old-Fashioned Rolled Oats
3/4 cup Granulated Sugar
1 tsp Baking Powder
1/2 tsp Fine Salt
3/4 cup Melted Vegan Butter
1 tsp Vanilla Extract

For The Blueberry Filling

3 cups Fresh Blueberries
1/3 cup Granulated Sugar
2 tbsp Cornstarch
1 tbsp Lemon Zest
2 tbsp Lemon Juice
1/2 tsp Vanilla Extract

How to Make It

Step 1

Preheat the oven to 350 degrees F and line an 8-inch square baking pan with parchment paper.

Step 2

Whisk the flour, oats, sugar, baking powder, and salt together. Stir in the melted vegan butter and vanilla until large, moist crumbs form.

Step 3

Reserve 1 cup of the crumble mixture. Firmly press the remainder into the prepared pan and bake for 12 minutes.

Step 4

Toss the blueberries with the sugar, cornstarch, lemon zest, lemon juice, and vanilla until evenly coated.

Step 5

Spread the blueberry filling over the warm crust. Scatter the reserved crumble evenly across the berries.

Step 6

Bake for 38 to 43 minutes, until the filling is bubbling around the edges and the crumble is golden.

Step 7

Cool the bars completely in the pan, then refrigerate for 1 hour before portioning so the blueberry layer sets cleanly.

Recipe Tips

Measure Your Flour The Right Way

Spoon the flour into your measuring cup and level it off with a knife. Don’t scoop the cup straight into the bag.

Scooping packs in way too much flour, and that makes your crust dry and crumbly instead of buttery and tender.

From my experience, this one little step makes a big difference in how the crumble holds together.

Press The Bottom Crust Down Firmly

When you press the crumble mixture into the pan for the base, really push it down so it’s packed tight and even. I like to use the flat bottom of a measuring cup to do this.

A loosely pressed crust falls apart when you cut the bars later. A firm, compact base gives you clean slices that stay in one piece.

Don’t Skip The Cornstarch Toss

Make sure every blueberry gets coated in the cornstarch and sugar mixture. Toss it well until you don’t see any dry powder.

The cornstarch is what thickens all that berry juice as it bakes. If it’s not spread evenly, you’ll end up with runny, soupy spots instead of a filling that sets up nicely.