This is so simple. Thanks to David Lebovitz, who I have been following for as long as he has been writing.
Topping
- 4 tablespoons unsalted butter, cubed and cold
- 1/2 cup sugar
- 1/3 cup flour
- 1/2 teaspoon cinnamon
Batter
- 6 tablespoons unsalted butter, at room temperature
- 1 cup sugar
- zest of 2 lemons (use the same lemons for the syrup, below)
- 1 1/2 cups + 2 tablespoons flour
- 1 teaspoon baking powder
- 1/4 teaspoon baking soda
- 1/2 teaspoon salt
- 1/2 teaspoon ground cinnamon
- 2 large eggs, at room temperature
- 1/2 cup buttermilk, at room temperature
- 3 cups blueberries
Lemon Syrup
- 1/3 cup sugar
- juice of 2 medium lemons (about 6 tablespoons)
Preheat the oven to 350. Grease a 9×9 square cake pan
In a small bowl, mix together all the topping ingredients by hand until it resembles little peas.
In a standing mixer, with the paddle attachment, cream together the butter, sugar, and lemon zest until light and fluffy. About 3 minutes. Add the eggs, one at a time, and mix. Scrape down the sides of the bowl.
Put the flour, baking powder, baking soda, salt, and cinnamon in a medium-sized bowl and whisk together.
With the mixture on low, add half the flour mixture, and then stir in the buttermilk. Take the bowl off and do the rest by hand. Add in the rest of the flour, and mix. Now add the blueberries and fold them in without smashing them up.
Scrape into the pan, top with the crumble and bake for about 50 minutes.
In a saucepan, make the lemon syrup. Mix together until the sauce gets caramelized almost like a light maple syrup. I made it in advance and reheated it when I took the cake