- Preheat and Prep: Preheat oven to 400F (200C). Line a baking sheet with parchment paper. 
- Dry Ingredients: In a large bowl, whisk together the gluten-free flour blend, sugar, baking powder, baking soda, and salt. 
- Cut in Butter: Cut in the cold butter using a pastry blender or your fingers until the mixture resembles coarse crumbs. 
- Wet Ingredients: In a separate bowl, combine the buttermilk and vanilla extract. 
- Combine Wet and Dry: Gradually add the wet ingredients to the dry ingredients, mixing until just combined. Do not overmix. 
- Drop Biscuits: Drop spoonfuls of dough (about cup each) onto the prepared baking sheet. 
- Bake: Bake for 20-25 minutes, or until golden brown. Let cool on a wire rack. 
- Prepare Strawberries: In a bowl, combine the sliced strawberries, sugar, and lemon juice (if using). Gently toss and let sit for at least 15 minutes to macerate. 
- Make Whipped Cream: In a chilled bowl, whip the heavy cream with powdered sugar and vanilla extract until stiff peaks form. 
- Assemble Shortcakes: Split the cooled shortcakes in half. Spoon the macerated strawberries over the bottom halves, top with whipped cream, and place the top halves of the shortcakes on top. Serve immediately. 
- Tips and Substitutions: For a dairy-free option, substitute the buttermilk with a non-dairy milk alternative and use a plant-based butter substitute. Coconut whipped cream can replace traditional whipped cream. The granulated sugar can be substituted with maple syrup. Ensure the gluten-free flour blend contains xanthan gum, or add it separately (about teaspoon per cup of flour blend).