Preheat the oven to 350 degrees F. Grease a 9” round cake pan and set it aside.
Make the Topping
In a large bowl, combine flour, granulated sugar, cinnamon and sea salt.
Add butter and cut in with a fork or pastry cutter or your hands until the mixture forms large crumbs.
Set aside.
Make the Cake
Combine flour, baking powder, sea salt and cinnamon in a small bowl. Set aside.
In the bowl of a standing mixer fitted with a paddle attachment (or in a large bowl with a handheld mixer) beat the butter and sugar together on high speed until light and fluffy – about 1 minute.
Add eggs and vanilla and beat on medium speed until just combined.
Then, add the sour cream and beat until smooth.
Add dry ingredients and beat on medium-high speed until combined.
Fold in the blueberries until evenly distributed throughout the batter.
Assemble & Bake
Spread the cake batter in an even layer in the prepared baking dish.
Sprinkle crumb topping over the batter.
Bake in the preheated oven for 40-45 minutes, or until the cake is puffed, no longer jiggly and a toothpick inserted in the center comes out clean or with a few moist crumbs.
Transfer to wire cooling rack until cooled completely.
Remove the cake from the pan and transfer it to a serving plate to cut & serve. Alternatively, you can cut individual pieces straight out of the pan and serve that way.
Video
Notes
Ingredient Substitutions
All-purpose flour. You can replace up to ¼ cup of the flour with whole wheat pastry flour. You can also use all-purpose gluten-free flour.
Salted butter. Unsalted butter works well in this recipe.
Granulated sugar. Organic cane sugar or white sugar are great choices.
Sour Cream. Full-fat is the best choice. You can use full-fat greek yogurt, if desired.
Blueberries. Fresh blueberries are the best choice. If you decide to use frozen, be sure to thaw and drain them fully. Then toss them with 1-2 TBS of flour before mixing them into the batter.
Store/freezeStore leftovers in an airtight container in the refrigerator for up to 5 days or in the freezer for up to 2 months. I suggest freezing in individual portions for easy removal and reheating.