Prepare the Baking Sheet: Line a baking sheet with parchment paper to prevent sticking and facilitate easy cleanup.

Mix Dry Ingredients: In a medium-sized bowl, whisk together the gluten-free multipurpose flour, baking powder, poppyseeds, and kosher salt.

Infuse Lemon Flavor: In a large mixing bowl, combine the granulated sugar and lemon zest, rubbing the zest into the sugar.

Combine Ingredients: Pour the dry mixture into the lemon-sugar mixture, gently folding until just incorporated.

Incorporate Cold Butter: Cut the cold unsalted butter into small cubes and mix until the texture resembles coarse crumbs.

Combine Wet Ingredients: In a separate bowl, whisk together kefir, egg, and lemon juice until frothy; then add to the dry mixture.

Shape the Dough: Transfer the dough to the lined baking sheet and shape into a rectangle measuring about 7×5 inches.

Create Layers: Fold the dough in half three times without kneading; chill briefly if sticky.

Final Shape & Chill: Shape the folded dough into a 6-inch circle, about ¾ inch thick, and refrigerate for at least 10 minutes.

Preheat and Cut the Dough: Preheat the oven to 400°F (200°C) and cut the chilled dough into 8 equal triangles.

Brush and Sprinkle: Brush the tops of the cut scones with kefir and sprinkle raw sugar over them.

Bake to Perfection: Bake for 22-26 minutes, or until golden brown on top.

Cool and Glaze: Allow to cool for about 10 minutes, then drizzle with glaze prepared from powdered sugar and lemon juice.