Place the berries in a colander and quickly rinse them under running cold water. Pour them on a pan or tray lined with several thicknesses of paper towel to drain for 5 minutes. Hull the strawberries with the point of a stainless steel paring knife, then slice them into a bowl. Sprinkle with the sugar and lemon juice, then set aside, covered at room temperature for an hour or two.
Whip the cream (add a couple of tablespoons of sugar, if you like) until it holds a soft peak, cover and refrigerate.
Preheat the oven to 450 degrees and set rack in the middle level.
In a food processor combine the self-rising flour and sugar and pulse to mix. Add the butter, cut into 8 to 10 pieces, and pulse until the mixture resembles coarse meal. Transfer the mixture to a large bowl and make a well in the center. With a fork stir in the buttermilk, being careful not to over work the dough. Let the dough stand for a minute or 2 to let the flours absorb the liquid. Flour the work surface and turn the dough out onto it. Fold the dough over on itself 2 or 3 times, until it is smooth and less sticky.
For a large shortcake, pat the dough into a 9-inch disk on parchment-lined cookie sheet. For individual shortcakes, pat the dough into a 6 by 12-inch rectangle and cut into 8 (3-inch) biscuits with a sharp, floured round cutter. Transfer to a parchment-lined cookie sheet. Paint the tops with the buttermilk and sprinkle with the sugar. Bake for 10 to 15 minutes, until well risen and golden brown. Check the center of the large shortcake with a toothpick to make sure it has baked through. If the pick emerges with dough clinging to it, lower temperature to 350 degrees and bake another 5 minutes.
Slide the large shortcake onto a platter immediately after it is baked. Use a sharp, serrated knife to slice through the middle, making two layers. Slide the edge of a cookie sheet between the two layers and lift the top layer off. Butter the bottom layer and pour on all but 1/2 cup of the berries.
Slide the top back on and pour the remaining berries on the top. Split the small shortcakes in the same way and place the bottoms on individual dessert plates. Butter them and top with about 1/3 cup berry mixture. Replace tops and pour a tablespoon or so on the top. Serve immediately, passing the cream in a bowl for the guests to help themselves.