Bursting Blueberry Cardamom Buckle

1. Preheat the oven to 350 degrees F. Grease a 9-inch spring form pan. 2. In a large bowl, whisk together the flour, baking powder, cardamom, and sugar. Add the butter, milk, eggs, and vanilla, mix until just combined. Spoon the batter into the prepared pan. Toss together the blueberries and lemon zest and sprinkle the blueberries over the batter.3. To make the crumble. Whisk together the flour, sugar, and cinnamon in a small bowl. Add the butter and mix with your hands until the mix is moist and a crumble forms. Sprinkle the crumble evenly over the fruit. 4. Transfer to the oven and bake for 45-55 minutes or until golden on top. If you insert a skewer into the center, it should come out almost clean. Let the cake cool 5 minutes. Serve warm or at room temp. Dust with powdered sugar, if desired.