Prep your tools. Preheat your oven to 375 F. Line an 8×8 baking dish with foil with some foil hanging over the edges. This will make it easy to lift the cake out of the pan later. Lightly spray the foil that’s inside the baking dish with PAM or cooking spray.

Make the topping. In a medium bowl, combine all of the topping ingredients. Mix well, then set aside.

Mix the dry cake ingredients. In a large bowl, combine the flour, sugar, baking powder and kosher salt. Mix well.

Add the wet ingredients. Make a well in the center of the dry ingredients. Add the eggs, buttermilk and cooled butter. Mix until just combined.

Add the blueberries. Fold the blueberries into the cake batter. Mix until no dry bits of batter are visible, making sure to scrap the sides and bottom of the bowl.

Add the topping. Pour the cake batter into the prepared 8×8 baking dish, then sprinkle the topping all over the cake batter.

Bake. Place the baking dish in the oven and bake for 40-45 minutes.

Add foil and raise the temperature. Around the 40 minute mark the topping will be golden but the center of the cake will still need to cook longer. Using oven mitts, remove the cake from the oven and cover it with another layer of foil, crimping down the edges to seal. Raise the temperature to 400F and place the cake back in the oven for another 10-15 minutes.

Test for doneness. After 10 minutes, remove the cake from the oven and lift the top layer of foil. Test the cake by pressing the center gently with your finger tip. (Careful, the cake will be hot.) If the cake is done the center will spring back when you gently press on it. If the cake needs more time, the indentation will not spring.

• If the cake is done, remove the top layer completely and allow the cake to cool for 15 min before slicing.
• If the cake is not done, seal the top layer of foil again and bake for another 5 minutes, until the center of the cake springs back.