Blueberry Brioche Crumb Cake

Ingredients:

For the Brioche Cake:

• 80g whole milk
• 1 teaspoon active dry yeast
• 1 tablespoon granulated sugar
• 160g all-purpose flour
• 3/4 teaspoon salt
• 1 egg, room temperature
• 56g unsalted butter, room temperature

For the Wild Blueberry Jam:

• 380g frozen wild blueberries
• 75g granulated sugar
• Zest of 1 lemon
• 32g cornstarch
• 42g lemon juice

For the Lemon Streusel:

• 45g unsalted butter
• 65g light brown sugar
• 90g all-purpose flour
• Zest of 1 lemon

Instructions:

1. Make brioche dough: In a microwave-safe measuring cup, heat milk to 100°F/38°C. Whisk in yeast and sugar. Set aside until the mixture begins to foam (~5 minutes).
2. Combine dry ingredients: Add flour and salt to the bowl of a stand mixer fitted with the dough hook attachment.
3. Add wet ingredients: When yeast mixture begins to foam, add it to the dry ingredients along with the egg and butter.
4. Knead dough: Knead on low speed for 1 minute, then increase to medium-high and knead for 15-20 minutes, or until the dough passes the windowpane test.
5. Rise: Cover dough and let it rise in a warm environment until doubled in size (approximately 1 hour).
6. Make wild blueberry jam: Add wild blueberries, sugar, and lemon zest to a medium saucepan over medium heat. Simmer for 5 minutes, stirring occasionally. Make a cornstarch slurry by whisking together lemon juice and cornstarch. Add slurry to the blueberry mixture, stirring constantly, until the jam thickens. Remove from heat and set aside.
7. Make lemon streusel: In a medium bowl, melt butter. Add sugar, flour, and lemon zest. Mix with a fork until clumpy.
8. Assemble cake: Line an 8" or 9" cake pan with parchment paper. Once dough has doubled in size, gently punch it down to remove excess air. Form the dough into a ball and place it in the prepared pan. Press the dough down into the pan to form an 8" circle. Cover with plastic wrap or a towel and let rise at room temperature until doubled in size (~30 minutes).
9. Preheat oven: Preheat oven to 350°F/175°C.
10. Add fillings: Spread wild blueberry jam evenly over the risen dough. Sprinkle lemon streusel over the jam.
11. Bake: Bake for 30-35 minutes, or until the internal temperature reaches 190°F/88°C.
12. Cool and serve: Let the cake cool to room temperature before slicing and serving.

Optional additions:

• For extra flavor: Add a pinch of ground cinnamon or nutmeg to the lemon streusel.
• For a richer filling: Increase the amount of chocolate hazelnut spread.
• For a sweeter filling: Add a tablespoon of honey or maple syrup to the wild blueberry jam.

Enjoy your delicious Lemon Blueberry Brioche Cake!