Preheat the oven to 350 and grease an 8x11 glass baking dish with butter and set it aside.
In a large bowl, add in the sugar and zest the lemon on top.
Press the zest into the sugar until it turns a pale yellow.
Add in the butter, and cream sugar and butter together using the hand mixer.
Mix in the eggs, then the sour cream and stir in the vanilla and set aside.
In a medium bowl, add in the flour, salt, baking soda and whisk.
Sift the dry ingredients over the wet ingredients and mix with a rubber spatula until just combined.
Gently fold in the blueberries.
Pour batter into the prepared dish and smooth it out.
Bake for 50 minutes to 1 hour. Check at the 50 minute mark as ovens vary and you don't want to over bake it.
You will know when its done when a tooth pick comes out clean from the center of the cake.
Place on a wire rack to completely cool before adding the glaze.
Mix all the glaze ingredients together in a small bowl, you can sift the icing sugar into the bowl before adding the rest of the ingredients for a smoother glaze.
Add the glaze on top of the cake with a silicon brush.
Slice and serve.
Notes
If you find the glaze it too thick add another tsp. of heavy cream and mix it in.
Store your leftover cake in an airtight container or cover dish with plastic wrap and store at room temperature for up to 3 days or in the fridge for up to five.