Clean, hull and slice the strawberries and put them into a large bowl. Crush half the strawberries with a potato masher or the back of the fork and toss in with the reserved sliced strawberries with the sugar. Set the bowl aside for at least 30 minutes to allow the sugar to dissolve and the strawberries to release their juice.
Make the Biscuits
Preheat the oven to 425° F (220° C) . Line a baking sheet with parchment paper.
In a food processor, pulse the flour, 3 tablespoons sugar, baking powder, and salt three times just to mix them up.
Slice the butter into 1/2 inch pieces and add to the food processor. Pulse until the mixture resembles coarse sand. About 15 - 20 pulses. Transfer to a large bowl.
In a small bowl, whisk the milk and egg together. Pour this into the flour mixture and stir until large clumps form. Knead with your hands until the dough comes together.
Divide the dough into six equal parts. Roll each section and then pat down to about 3/4" tall and place them on the prepared baking sheet.
Brush the tops of the biscuits with the egg white, then sprinkle on the remaining granulated sugar.
Bake for 12 - 14 minutes. The biscuits should be golden brown on top. Remove from the oven and cool on a wire rack for 10 minutes.
Make the Whipped Cream
When you are ready to serve your shortcakes, whisk your heavy cream, sugar, and vanilla with a stand mixer or hand mixer. Whip until soft peaks form.
Assemble your shortcakes. Split the biscuit in half. Spoon the strawberries over the bottom biscuit, top with whipped cream, and add the top of the biscuit like a sandwich.
Notes
The strawberries may take up to 2 hours to completely soften and macerate.The unbaked biscuits can be refrigerated for up to 2 hours.Bakes and cooled biscuits can be stored at room temperature for a day. Before assembling, I like to warm them back up in my toaster oven at 350 for 3 minutes.