Step 1

Preheat the oven to 350F. Prepare a 9-inch springform pan with oil (and parchment on the bottom if desired).

Step 2

In a bowl add brown sugar, flour, oats, cinnamon, and salt. Cut the butter in until a coarse crumble forms. Set the bowl aside.

Step 3

In a large bowl mix together flour, sugar, baking powder, baking soda, cardamom, cinnamon, and salt. Cut the cold butter into the dry ingredients with a pastry cutter, forks or fingers (make sure your hands are not too warm) combine until the mixture resembles a coarse meal.

Step 4

Whisk together oil, milk, sour cream, eggs, vanilla, lemon zest and juice.

Step 5

Fold the wet ingredients gently into the flour mixture. It will be thick.

Step 6

With a rubber spatula spread 2/3 of the mixture in the pan and sprinkle 1 cup of the berries evenly on top. Spread the remaining batter on the top (drop small scoops evenly around and spread the dough over the berries). Top with the remaining blueberries. Spread the streusel evenly over the top.

Step 7

Bake at 350F for 55-70 minutes, until set in the middle.

Step 8

Cool on a wire rack for 20-30 minutes before cutting.