Hull the strawberries and slice into 1/4-inch thick pieces. In a medium bowl, gently stir together sliced strawberries, granulated sugar, lemon juice, and lemon zest until well coated. Let sit for 20 minutes until glossy syrup forms.
Preheat the oven to 425°F. Line a baking sheet with parchment paper.
In a large bowl, whisk together flour, granulated sugar, baking powder, and salt.
Cut in cold unsalted butter using a pastry cutter or fork until the mixture forms coarse crumbs.
In a medium bowl, whisk cold heavy cream, egg, and vanilla bean powder until combined. Gradually add this to the dry ingredients, gently mixing with a rubber spatula just until a dough forms.
Turn the dough onto a lightly floured surface. Roll out to 1/2-inch thickness. Use a round biscuit cutter or drinking glass to cut out 6 shortcakes. Place on the prepared baking sheet.
Brush the tops of the shortcakes with 1 tablespoon heavy cream, then sprinkle with coarse sugar.
Bake for 15 minutes or until golden brown on top and firm to touch. Let cool slightly.
In a large bowl, use a hand mixer or sturdy whisk to beat cold heavy whipping cream, powdered sugar, and vanilla bean powder on medium-high speed until soft peaks form. Transfer to a serving bowl.
To serve, split each shortcake in half and layer with a generous amount of strawberries and their syrup, then top with a dollop of whipped cream.