Cut the butter into small cubes and place on a plate in the freezer for at least 15 minutes—this ensures it stays cold and creates those desirable flaky layers in the scones. While the butter chills, hull and dice the strawberries into roughly 1/2-inch pieces, then set aside on a paper towel to absorb excess moisture. Sift the confectioners sugar to remove any lumps, and have all other ingredients measured and ready. I always sift my dry ingredients together before adding anything else—it aerates the flour and ensures even distribution of the baking powder.
In a large bowl, whisk together the flour, sugar, lemon zest, baking powder, poppy seeds, and salt. Using a box grater or the large holes of a standing grater, grate the frozen butter directly into the dry mixture, working quickly so the butter stays cold. Using a fork or pastry cutter, gently toss and break up the butter pieces until the mixture resembles coarse breadcrumbs with pea-sized pieces of butter visible throughout. Don't overmix—these butter pieces are what create the flaky texture, so stop as soon as everything is evenly combined.
In a small bowl, whisk together the cream, egg, and vanilla until well combined. Pour this wet mixture into the dry ingredients from Step 2, then add the diced strawberries. Using a rubber spatula or wooden spoon, gently fold everything together just until a shaggy dough forms—do not overmix, as this develops too much gluten and makes tough scones. The dough should come together but still look a bit rough and have visible strawberry pieces and streaks of color.
Turn the dough out onto a lightly floured surface and gently pat it into an 8-inch disc about 3/4-inch thick. Using a sharp knife, cut the disc into 8 equal wedges like a pie. Arrange the wedges on a parchment-lined baking sheet, spacing them about 2-3 inches apart. Brush the top of each scone with the 1 tablespoon of cream, then sprinkle evenly with coarse sugar for a professional-looking finish. Transfer the baking sheet to the freezer for at least 15 minutes while you heat the oven—I find this chilling step is crucial because it keeps the scones tender and prevents them from spreading too much during baking.
Preheat the oven to 400°F. Once the oven reaches temperature and the scones have chilled for at least 15 minutes, place the baking sheet on the middle rack. Bake for 22-25 minutes, until the scones are golden brown on the edges and a toothpick inserted into the center comes out with just a few moist crumbs. Don't overbake—scones are best when they're still slightly tender inside with a crispy exterior.
While the scones bake, whisk together the sifted confectioners sugar, lemon juice, and 1 1/2 tablespoons of cream in a small bowl until you reach a pourable consistency—it should be thick enough to cling to the scones but thin enough to drizzle. If the glaze is too thick, add a teaspoon more cream; if too thin, add a bit more sugar. As soon as the scones come out of the oven, drizzle the glaze generously over the warm scones, allowing it to pool slightly on the tops and run down the sides. The warmth of the scones will help the glaze set slightly. Let cool for a few minutes before serving.