Stir the strawberries and ¼ cup (50g) granulated sugar together in a large bowl. Cover and set in the refrigerator until ready to use.

Preheat oven to 400°F (204°C). Mix the flour, granulated sugar, baking powder, baking soda, and salt together in a large bowl or in a large food processor. Whisk or pulse until combined.

Add the cubed butter and cut into the dry ingredients with a pastry cutter or by pulsing several times in the processor. Pulse until coarse crumbs form.

Pour buttermilk on top. Fold everything together with a large spoon or silicone spatula until it begins to come together. Do not overwork the dough.

Pour the dough and any dough crumbles onto a floured work surface and gently bring together with generously floured hands.

Using floured hands or a floured rolling pin, flatten into a ¾ inch thick rectangle. Fold one side into the center, then the other side. Turn the dough horizontally. Gently flatten into a ¾ inch thick rectangle again. Repeat the folding again. Turn the dough horizontally one more time. Gently flatten into a ¾ inch thick rectangle. Repeat the folding one last time.

Cut into 2.75 or 3-inch circles with a biscuit cutter. Re-roll/flatten any scraps and cut more circles until you have around 10-12 biscuits.

Arrange in a 10-inch cast iron skillet or close together on a parchment paper or silicone baking mat lined baking sheet. Make sure the biscuits are touching.

Brush the tops with 2 Tablespoons heavy cream or buttermilk and sprinkle with coarse sugar. Bake for 18-22 minutes or until biscuits are golden brown on top. Remove from the oven, then cool in the pan for at least 10 minutes before assembling.

Using a hand mixer or a stand mixer fitted with a whisk attachment, beat the heavy cream, 2 Tablespoons granulated sugar, and vanilla on medium-high speed until soft-medium peaks form, about 3 minutes.

Slice the biscuits in half and layer with strawberries and whipped cream. Serve immediately.