Preheat the oven and prep the pan: Preheat the oven to 350°F and position a rack in the center. Lightly butter an 8-inch springform pan and dust with flour.

Mix the flour with baking powder and salt: In a medium bowl, vigorously whisk together 1 cup of the flour with the baking powder, salt, and cinnamon. Set aside.

Make the batter: Using an electric mixer, beat the butter on medium high speed for 2 minutes. Add the sugar and beat until light and fluffy, a 1-2 minutes more. Beat in the vanilla extract. Add the eggs one at a time and beat until well blended and scraping down the sides of the bowl as needed. Beat in the lemon zest, if using. Reduce the speed of the mixer to low and slowly add the flour mixture, beating until smooth. The batter will be thick.

Put the batter in the pan: Put the batter in the prepared pan, smoothing the top with a spatula.

Scatter the berries over the batter: Combine the berries with the remaining teaspoon of flour and the lemon juice in a bowl. Spoon the berry mixture over the batter.

Bake: Bake for 45 to 55 minutes at 350°F, or until a tester inserted into the center comes out clean. Remove from the oven and let the cake cool in the pan for 10 minutes. Carefully slide a thin knife around the edges of the cake to release it from the pan.

Dust with powdered sugar to serve: Transfer the cake to a platter, berry side up. Dust the cake with powdered sugar to serve.