Preheat oven to 425°F (220°C) and line a baking sheet with parchment paper.

In a large bowl, whisk together flour, sugar, baking powder, and salt.

Using a pastry cutter or two knives, cut the cold butter into the flour mixture until it resembles coarse crumbs with pea-sized pieces remaining.

Gently fold in the fresh blueberries and lemon zest to distribute evenly without crushing the berries.

Pour in the cold buttermilk and stir with a spatula until a shaggy dough just begins to form.

Turn dough onto a lightly floured surface; pat into a rectangle and fold in thirds like a letter to create layers. Repeat folding process twice.

Pat dough to a 1-inch thickness and cut into 8 rounds using a 2.5-inch biscuit cutter, pressing straight down without twisting.

Place biscuits on the prepared baking sheet and bake for 12 to 15 minutes until tops are golden brown.

Whisk powdered sugar and lemon juice until smooth to create the glaze.

Drizzle glaze over the biscuits while they are still slightly warm and serve immediately.