Preheat the oven to 350 degrees F and grease an 8-inch round pan. I also like to place a round of parchment paper on the bottom for easy removal.
In a large bowl, combine the flour, sugar, baking powder and salt. Whisk well.
Now add the melted vegan butter, milk, lemon zest, lemon juice and vanilla to the dry ingredients. Stir with a large spoon until just combined, being careful not to over mix.
Add half of the blueberries to the batter and gently fold them in.
Pour the batter into the prepared pan. Scatter the other half of the blueberries all over the top, pressing some of them into the batter just a little bit.
Bake for 1 hour, or until a toothpick inserted in the middle comes out clean with no wet batter on it.
Let the cake cool in the pan for 15 minutes, then carefully transfer it to a cooling rack (you can also just leave it in the pan and serve from there if you don't want the hassle of moving it).
Right before you're ready to serve the cake, dust it with powdered sugar.