Add 2 cups of flour (250 grams), baking soda, baking powder, and ½ cup of sugar to a large mixing bowl and whisk to combine.
Add the butter to the bowl and work it into the dry ingredients with your hands until it resembles moist crumbs.
Add the buttermilk to the bowl and stir until the dough comes together.
If the dough is too wet, add the remaining flour, ¼ cup (25-30 grams) at a time, until it reaches a biscuit-dough consistency.
Turn the dough out onto a moderately floured surface, knead it a few times, and form it into a 7-inch (18 cm) square.
Cut the dough into 9 equal-sized squares.
Arrange the squares on a greased and lightly floured baking sheet.
Bake the shortcakes in the preheated oven for 12-14 minutes, or until the bottoms are golden brown. Transfer the shortcakes to a wire cooling rack to cool completely.
While the shortcake biscuits are baking and/or cooling down prepare the strawberry filling. Sprinkle two tablespoons of sugar over the chopped strawberries and stir to combine. Set aside.
Once the shortcakes are cooled, cut them in half lengthwise, and layer the prepared strawberries and whipped cream on the bottom half.
Place the top half back on and top with extra whipped cream and strawberries.