Place the sliced strawberries in a bowl. Add the jar of strawberry preserves and gently mix. Set the strawberries aside to macerate while making the biscuits.

Preheat oven to 475 degrees. Add the biscuit mix to a bowl. With a cheese grater, grate the butter into the mix. With your fingers, work the butter into the flour. Add the buttermilk and stir until the dough just comes together. Take care not to overwork.

Turn the dough out on a well-floured work surface and dust the top with flour. Using your hands, press it into a ½” thick rectangle (approx. 5 x 15”). Starting at one of the short ends, fold the dough in fourths. Rotate 90 degrees and repeat the pressing and folding two more times.  

Press the dough into a rectangle, about 1” thick. Using a 3” biscuit cutter, cut seven biscuits, reshaping, and cutting dough scraps as needed. Place biscuits on a parchment lined 8x8” baking tray or 9” cake pan. You want the biscuits touching their neighbors, so crowd the pan. Place in oven and turn heat down to 350 degrees. Bake for 17-20 minutes, until golden and cooked through. 

While the biscuits bake, make the whipped cream. Place the heavy cream in a large metal bowl and whip with a whisk until soft peaks have formed. Add the powdered sugar and vanilla extract and continue to whip until the cream can hold a firm peak.
 
To serve, split the biscuits, top with few generous spoonfuls of the macerated berries and whipped cream.