Line a baking sheet with parchment paper.
In a large bowl, mix the flour, sugar, baking powder, and salt.
Add the cold vegan butter to the flour mixture. Use a pastry cutter or a fork to work the butter into the flour until the mixture resembles coarse crumbs. Alternatively, you can grate the butter and then mix it with the dry ingredients.
Add the yogurt, sourdough starter, and vanilla extract. Gently fold them into the flour mixture until just combined.
Carefully fold in the dried strawberries, being careful not to overmix.
Place the dough onto the prepared baking sheet and shape it into a circle.
Cut the circle into 8 pieces and freeze the scones for 20 minutes to firm them up.
Meanwhile, preheat the oven to 200°C
Remove the scones from the freezer and brush the tops with yogurt.
Bake the scones in the preheated oven for about 22–26 minutes, until golden brown.
Remove from the oven and let them cool on a wire rack.
Dust with powdered sugar if desired.