Prep your tools and ingredients: Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper. Stick your butter in the freezer for 10 minutes and keep the cream cold. Cold fat equals flaky scones.

Mix dry ingredients: In a large bowl, whisk 2 cups all-purpose flour, 1/3 cup granulated sugar, 1 tablespoon baking powder, and 1/2 teaspoon fine sea salt. Whisk in the zest of 1 large lemon, rubbing it into the sugar and flour with your fingers to release the oils.

Cut in the butter: Grate 1/2 cup (1 stick) cold unsalted butter on the large holes of a box grater, or cut into pea-size pieces. Toss into the flour mixture. Use your fingertips or a pastry cutter to distribute until you have a mix of pea to nickel-sized bits. Don’t overwork it.

Combine wet ingredients: In a measuring cup, whisk 1/2 cup cold heavy cream, 1 large egg, 1 teaspoon vanilla, and 1 tablespoon fresh lemon juice. Reserve an extra tablespoon or two of cream for brushing.

Bring the dough together: Pour the wet ingredients into the dry. Stir with a fork until shaggy and just combined. If it looks dry, add 1–2 teaspoons more cream. The dough should look slightly rough and a bit sticky, not wet.

Shape gently: Turn the dough onto a lightly floured surface. Pat into a 6–7 inch round, about 1 inch thick. Fold the dough in half, then pat back into a round. This quick fold boosts layers. Cut into 8 wedges with a sharp knife or bench scraper.

Chill before baking: Transfer wedges to the baking sheet, spacing them out. Brush tops with a little cream and sprinkle with coarse sugar if using. Chill the tray in the fridge for 10–15 minutes. This helps them rise tall.

Bake: Bake for 15–18 minutes, until tops are golden and the edges look set. The centers should spring back when gently pressed. Let cool on the sheet for 5 minutes, then move to a rack.

Make the glaze: In a small bowl, whisk 1 cup powdered sugar with 2–3 tablespoons fresh lemon juice until smooth and pourable. Add a pinch of zest for extra brightness if you like.

Glaze and serve: Drizzle over warm (not hot) scones and let set for a few minutes. Serve slightly warm or at room temperature.