In a small bowl, combine the wet ingredients and whisk until smooth. Set aside until ready to use.
In a large bowl, combine the flour, baking powder, sugar, and salt. Then, using a cheese grater, grate your frozen butter into your flour mixture and gently mix with your hands until just combined.
Add the lemon zest and mix, then add the washed blueberries and toss gently to coat the berries in the flour.
Pour the wet ingredients into your large mixing bowl. Then, using your hands, carefully mix everything until the mixture forms a ball. Doing your best not to squish all the berries!
Wash your hands and line a large baking sheet with parchment paper.
Turn your scone dough out onto your prepared baking sheet. And using your hands, gently press it out until it is roughly an 8 inch circle, about 1/2-1 inch thick.
Then, using a sharp knife, cut your circle into 8 triangles(like a pie). Now you can either separate your scones now, so that they aren’t touching, or wait to separate them until after they have chilled. If your scones are more on the sticky/wet side, I would recommend waiting until after they have chilled.
Place your baking sheet in the fridge and allow the scones to chill/ferment for at least 30 minutes(see notes for how to ferment longer)
After 30 minutes, preheat your oven to 400 degrees F. Remove your unbaked scones from the fridge and separate if needed, so they are not touching each other.
Brush the top of your scones with heavy cream, and then sprinkle a generous amount of sugar over the tops
Put your scones in the oven and bake for 20-25 minutes, or until golden brown.
Allow the scones to cool on the baking sheet until ready to serve. Scones can be served warm, but I find they taste better once they have cooled to room temperature.
Enjoy!