Preheat the oven to 350°F/175°C. Grease an 8 inch spring form pan and line with parchment paper.
In a medium bowl, combine all of the topping ingredients except for the flaked almonds. Mix together with your fingers until it resembles coarse sand. Set to the side.
In the bowl of a stand mixer fitted with the paddle attachment, cream together your butter and sugar on medium-high speed for 2-3 minutes until light and fluffy. While the mixer is on low speed, add the eggs one at a time. Scrape the bowl before each addition.
In a separate bowl, whisk together the flour, ground almonds, baking powder and salt. In a jug, whisk together the milk, vanilla extract, almond extract and yogurt.
Add the flour in three additions, alternating with the milk mixture, starting and ending with the flour. Fold in your lemon zest.
Toss your blueberries with 1 tablespoon of flour.
Pour the batter into the pan and then sprinkle your blueberries on top.
Bake for 1 hour and 20 minutes. Once you have 20 minutes left in the oven, take out the cake and sprinkle over the streusel and the flaked almonds.
Your cake is ready when a toothpick inserted comes out clean.