Blueberry Crumb Cake

5 from 21 votes

This Blueberry Crumb Cake has mountains of buttery crumbs topped with sugar, a soft thin cake and a sweet layer of blueberry jam. You can even top this berry crumb cake with a blueberry glaze! It's everything you adore about New York Crumb Cake but slightly sweeter and perfect for any berry lover! Best part is, you would never know it's gluten free, eggless, nut free and can easily be dairy free (vegan)!

Prep Time20

Cook Time35

Cool Time30

Total Time1 25

Course: Dessert

Cuisine: American

Diet: Gluten Free, Vegan

Servings: squares

Calories: 383kcal

Author: Lee

Ingredients

For the Blueberry Jam:

2 cups blueberries , fresh or frozen
½ lemon , juiced and keep the peel
¼ cup granulated sugar
¼ cup water
1 pinch kosher salt

For The Crumb Cake:

1.5 cups multipurpose gluten free flour (I use a gluten free multipurpose flour with xanthan gum already in it)
½ cup granulated sugar
2.5 teaspoons baking powder
½ teaspoon kosher salt
2 heaping tablespoons cornstarch mixed with 3 tablespoons water
¾ cup milk
2 tablespoons vegetable oil
2 teaspoons pure vanilla extract

For the Crumb Topping:

1 cup unsalted butter or vegan baking sticks, melted and cooled
2.5 cups multipurpose gluten free flour
1 cup light brown sugar , packed
1.5 teaspoons ground cinnamon
confectioners' sugar for dusting

For the Blueberry Glaze:

1 cup confectioners' sugar
1 tablespoon blueberry jam
2 tablespoons water

US Customary - Metric

Instructions

For The Blueberry Jam (make ahead of time)

Place the 2 cups blueberries, the juice of ½ lemon, lemon peel of ½ lemon, ¼ cup granulated sugar, ¼ cup water and the 1 pinch of kosher salt together in a saucepan. Cook over medium heat, stirring frequently and smashing the blueberries with the back of a spoon for about 15 min until the mixture begins to boil.
Once boiling, turn the heat to low and let simmer for 10 minutes, stirring frequently. Remove from heat to let thicken. Once completely cool, transfer to an airtight container and refrigerate.

For the Crumb Cake

Preheat the oven to 325 degrees Fahrenheit. Line a 9x12 baking dish with parchment paper, leaving a 1 inch overhang on either side. Lightly grease the parchment with vegetable oil. Set aside.
In a medium bowl, whisk together the 1.5 cups gluten free flour, ½ cup granulated sugar, 2.5 teaspoons baking powder and ½ teaspoon kosher salt.
In a large bowl, using a spoon, mix together the 2 heaping tablespoons cornstarch and the 3 tablespoons water until thin and watery. It will be thick and tacky at first.
Into the cornstarch water, whisk in the ¾ cup milk, 2 tablespoons vegetable oil and 2 teaspoons pure vanilla until combined.
Pour the dry ingredients into the wet, a little bit at a time. Once it gets too thick to whisk, switch to using a spatula.
Using a butter knife or an icing spatula, spread the batter into the prepared baking dish and smooth it out. It’s a little difficult because the batter is so thick.
Dollop 3 tablespoons worth of blueberry jam all over the top of the batter. Make sure not to use any excess liquid. You can strain the 3 tablespoons if need be (if your jam is super liquidy).
Gently use a butter knife to push the jam around so it coats the batter evenly.
Cut the 1 cup butter or vegan baking stick into pieces and place in a heat safe bowl. Microwave in 20 seconds increments, stirring after each time until melted. Set it aside to cool.
In a medium bowl, whisk together the remaining 2.5 cups of gluten free flour, the 1 cup light brown sugar and the 1.5 teaspoons ground cinnamon.
Pour in the melted butter and stir with a spatula until large crumbs form.
Sprinkle the crumbs all over the batter. There are lots of crumbs, make sure to use them all and cover every inch of batter. The crumbs will pile on top of one another; that's normal.
Bake the cake in the center rack of the oven for 33-35 minutes. You can use a toothpick inserted in the center, to make sure it comes out clean.
Let cool in the pan completely before removing. Once cool, use the parchment overhang to lift the cake out.
Once cool, dust the entire cake with a lot of confectioners' sugar. Cut the cake into squares.

For The Blueberry Glaze

Whisk the 1 cup confectioners' sugar, the 1 tablespoon blueberry jam and the 2 tablespoons water together in a small bowl.
Drizzle the blueberry glaze over top of the crumb cake squares and let harden.

Video

Notes

For the Jam: Make the jam one day prior to making the cake. It takes a while for the jam to reduce down and then cool. The jam must be thick; it cannot be watery like a blueberry sauce otherwise a wet layer will form under the jam.

Vegan: Use a dairy free gluten free flour, vegan sugar, vegan baking sticks and a non-dairy milk.

All Purpose Flour: I cannot test this due to celiac disease, but use 1.5 packed cups of regular flour in the dough (252 grams) and ½ cup plus 2 tablespoons of milk.

Storing without Glaze: Store the cake slices in foil in at room temperature for up to 2 days without the glaze and then add the glaze prior to serving. The squares tend to get wet on top with the glaze after storing. Do not store in an airtight container; the bottoms of the cakes will be wet and soggy.

Storing with Glaze: Once the glaze has completely hardened on the squares, wrap each square in aluminum foil. Try to create a teepee with the top of the foil so it isn't touching the top of the cake as much. This will prevent them from getting super wet on top. Store in the fridge for up to 2 days. Make sure to bring to room temperature prior to serving or they will be very hard. Or you can warm them in the microwave for a few seconds. Be careful not to burn your mouth.

Freezing: Store crumb cake without glaze wrapped in foil in the freezer for up to 30 days. Do not freeze with the blueberry glaze as it will make the cake wet when defrosting.

To defrost, take out if the freezer and leave at room temperature until soft; about 2 hours.

Nutrition