Preheat your oven to 350°F.
In a medium mixing bowl, combine the granulated sugar and lemon zest – work it together with your fingers so the lemon essence spreads all throughout the sugar.
To the lemon sugar, add the wet ingredients – eggs, vanilla, oil, fresh lemon juice, and mascarpone – whisk together.
To the combined liquids, add the dry ingredients – flour, baking powder, and salt. Mix until almost fully combined.
Add most of the blueberries and fold into the batter until everything is fully combined.
Pour the cake batter into the baking pan, top with a the remaining blueberries and turbinado/raw sugar.
Bake in a preheated oven at 350 for 50-60 minutes until the top is golden and a cake tester comes out without wet batter. Let it cool in the pan for 15 minutes to set, then take it out and put it on a cooling rack.