Add sliced strawberries to a bowl with sugar and lemon juice.
Stir and let sit 20–30 minutes until the berries release their juices. Stir once or twice to help them along.
Heat oven to 425°F (220°C). Line a baking sheet with parchment.
Whisk flour, sugar, baking powder, and salt in a large bowl.
Cut in the cold butter with a pastry cutter or your fingertips until you see pea-size bits of butter throughout.
Combine buttermilk and vanilla. Drizzle over the flour mixture. Toss with a fork until clumps form and the dough looks shaggy. If dry flour remains, add 1–2 teaspoons buttermilk at a time just until it comes together.
Turn dough onto a lightly floured surface. Gently bring it together and pat into a 1-inch-thick rectangle. Do not overwork.
Fold the rectangle in half like a book, pat back to 1 inch thick, and repeat once more for extra flaky layers.
Use a 2 1/2–3-inch round cutter to punch out shortcakes. Press straight down—don’t twist. Gather scraps gently and cut again.
Place on the baking sheet. Brush tops with cream or milk and sprinkle with sugar for sparkle and crunch.
Bake 13–16 minutes until risen and golden brown. Cool on a rack for 10 minutes.
Beat heavy cream, powdered sugar, vanilla, and a pinch of salt to soft or medium peaks. Keep it cloudy and soft, not stiff and dry.
Split warm or room-temp shortcakes with a serrated knife.
Spoon strawberries and plenty of their syrupy juices over the bottom half.
Add a generous dollop of whipped cream. Cap with the top half and serve right away.
