Step #2 Lightly grease a 9-inch springform pan & dust with flour.
Step #3 (You can also make this cake in a 9-inch cake pan that has been greased & dusted with flour, & lined on the bottom with parchment paper.
Step #4 ).
Step #5 In a bowl, mix 1 c of the flour with baking powder & salt & set aside.
Step #6 Using an electric mixer on medium-high to high speed, cream the butter, sugar & vanilla until light & fluffy, about 3 mins.
Step #7 Add the eggs one at a time & continue beating until well mixed.
Step #8 Reduce the speed to low & slowly add the flour mixture.
Step #9 Beat until smooth.
Step #10 pour the batter into the prepared pan.
Step #11 In a medium bowl, mix the blueberries with the remaining tsp of flour & the lemon juice.
Step #12 Spoon berry mixture over batter.
Step #13 Bake for 1 hr at 350° or until a cake tester or toothpick inserted in the center comes out clean.
Step #14 Remove from the oven & let the cake cool in the pan for 10 mins.
Step #15 If using a springform pan, slide a thin knife around the edges of the cake to release it from the pan before you release & remove the springform.
Step #16 (If using a cake pan, slide a knife around the edges of the cake & invert it onto a cake rack.
Step #17 Transfer the cake to a platter, berry side up.
Step #18 ) Dust with confectioner's sugar before serving.