Preheat oven to 350°F (175°C). Grease a 9-inch round cake pan and line the bottom with parchment. In a bowl, whisk flour, baking powder, baking soda, and salt.
In a large bowl, cream butter and sugar until light and fluffy (about 2-3 minutes). Beat in eggs one at a time. Add lemon zest, lemon juice, and vanilla; mix well.
Mix in sour cream. Add dry ingredients in three additions, alternating with milk, beginning and ending with flour. Mix until just combined.
Toss blueberries with 1 tbsp flour (prevents sinking). Gently fold into batter.
Spread batter evenly in the pan. Bake 45–50 minutes, until a toothpick comes out clean. Cool in pan 10 minutes, then transfer to a rack.
Whisk powdered sugar and lemon juice until smooth. Drizzle over cooled cake. Slice and enjoy!