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 with with a blueberry glaze drizzle. It's everything you adore about New York Crumb Cake but slightly sweeter. Best part is, you would never know it's gluten free, eggless, nut free and can easily be dairy free (vegan)!
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 gluten free flour, granulated sugar, baking powder and salt.
In a large bowl, using a spoon, mix together the cornstarch and water until thin and watery. It will be thick and tacky at first.
Into the cornstarch water, whisk in the milk of choice, oil and 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. You will need to 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 it around so it coats the batter evenly.
Cut the butter 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 gluten free flour for the crumb topping, the light brown sugar and the cinnamon.
After it's combined, 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. They 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 interred to make sure it comes out clean.
Let the crumb cake cool in the baking pan completely before trying to remove.
When cool, use the parchment overhang to lift the cake out. Make sure the cake is not hot otherwise it will fall apart into a giant mess.
Once cool, dust the entire cake with confectioners' sugar. A LOT of sugar. Cut the cake into squares.
For The Blueberry Glaze
Whisk the confectioners' sugar, the blueberry jam and the water together in a small bowl.
Drizzle over top of the crumb cake squares.
Video
Notes
Storing: Wrap extra squares individually in foil and then pop them in a zip top bag at room temperature for up tp 3 days.Freezing: Wrap extra squares individually in foil and then pop them in a zip top bag and freeze for up to 30 days. To defrost, leave the squares wrapped in foil at room temperature until soft. It might take 1-2 hours. For vegan: Use vegan baking sticks, a non dairy milk and a gluten free flour that is free from dairy.