Preheat your oven to 350F. Line your baking pan with parchment paper and spray with non-stick cooking spray.
In a bowl whisk together the flour, baking powder, lemon zest (careful not to zest the white pith of the lemon), salt and cinnamon.
Using your kitchen aid mixer (with a paddle attachment) or hand mixer cream together the butter and sugar until fluffy about 2 minutes. Add in the egg, vanilla, lemon juice. Mix until combined.
You will want to fold the dry ingredients and milk into the wet ingredients alternating between dry ingredients and milk, ending with flour.
Divide the flour into thirds, it does not have to be exact, but just know you will add the flour three times. The milk will be divided into half. To the wet ingredients (egg mixture) you will add one third of the flour, folding it in with a spatula. Then you will add one half of the milk, folding with a spatula. Repeat and then fold in your last third of flour. Folding means that instead of stirring you will lift the ingredients up from the bottom and fold it on top until it’s combined evenly. This will help create air for a lighter batter.
The batter will be very thick.
Fold in the blueberries. If you use frozen blueberries, there will be more of a blue color streak in your batter.
Pour the batter into your prepared pan.
Bake at 350F for 40-45 minutes. A toothpick should come out clean.
Let it cool on a rack completely before removing from the pan. This will help the cake from breaking apart. The easiest way is to lift up with using your parchment paper.
Drizzle with Lemon Glaze.
In a bowl mix together your powdered sugar and lemon juice. Add 1 TBSP of lemon juice at a time, whisking with a fork until you reach the consistency you want. (See blog for notes on the glaze)