Step 1

Preheat oven to 400°. Whisk egg, buttermilk, vanilla, and ¼ cup cream in a small bowl to combine. Whisk flour, granulated sugar, baking powder, salt, and baking soda in a large bowl. Using a pastry blender or your fingers, work butter into dry ingredients until mixture resembles coarse meal. Add halva and chocolate; toss to combine. Drizzle in egg mixture and stir with a fork until crumbly but incorporated.

Step 2

Turn out dough onto a parchment-lined baking sheet. Knead once or twice to bring together, then pat into a 6" square. Using a bench scraper or a knife, cut into 8 equally sized rectangles; space apart. Brush tops with cream, then sprinkle with sanding sugar.

Step 3

Bake biscuits until golden brown and a tester inserted into the center comes out clean, 20–25 minutes.Do ahead: Biscuits can be formed (but not baked) 1 month ahead. Freeze on baking sheet until solid, then transfer to freezer bags. Bake from frozen.

Step 4

While the biscuits are baking, combine strawberries, lemon juice, and 3 Tbsp. granulated sugar in a medium bowl. Let sit, tossing occasionally, until juicy and glossy, about 10 minutes.

Step 5

Whisk cream and remaining 3 Tbsp. granulated sugar in a chilled large bowl to medium-stiff peaks.

Step 6

To serve, split biscuits and spoon some whipped cream and berries over bottoms. Top with remaining biscuit halves and spoon remaining whipped cream and berries over.