1/3 cupcupgranulated sugar(plus extra for sprinkling)
1teaspoonbaking powder
1/2teaspoonsalt
1/4teaspoonbaking soda
1/2cupplain Greek yogurt
1largeegg
1teaspoonvanilla
1/2cupwhite chocolate chips or chunks
coarse sanding sugaror turbinado sugar optional, for sprinkling on top of scones
Instructions
Heat oven to 400°F and move rack to lower middle position. Toss the sliced rhubarb with 1 Tablespoon of sugar. Spread evenly over a baking sheet lined with a silicone baking mat or parchment paper and roast for 15-20 minutes, stirring halfway through. Set aside to cool. (Keep oven on to cook the scones)
Grate 8 Tablespoons frozen unsalted butter using the large holes of a box grater. Transfer butter to a plate and place in the freezer to keep cold.
Whisk together 1 1/2 cups all purpose flour, 1/2 cup whole wheat flour, 1/3 cup cup granulated sugar, 1 teaspoon baking powder, 1/2 teaspoon salt, and 1/4 teaspoon baking soda in a large bowl.
Whisk together1/2 cup plain Greek yogurt, 1 large egg, and 1 teaspoon vanilla in a medium bowl.
Stir the grated butter into the flour mixture until well incorporated. Stir in the yogurt mixture with a spoon or spatula. When most of the flour has been incorporated, transfer to a clean countertop and gently knead until no floury bits are left. Form into a 6x4" rectangle and place in the freezer on a plate for 10 minutes, until slightly chilled.
Place the dough on a lightly floured countertop, and lightly dust the top with flour. Roll into a 12" square. Spread the roasted rhubarb and 1/2 cup white chocolate chips or chunks evenly over the dough. Using a bench scraper to help remove the dough from the counter, roll the dough into a log (as if you were making cinnamon buns). Press the log into a 4x12" rectangle and cut into 8 triangles (cut in half, then cut each half in half to form squares, then cut each square in half on the diagonal to form triangles).
Place the triangles on a baking sheet lined with a silicone baking mat or parchment paper, and sprinkle lightly with coarse sanding sugar or turbinado sugar (use about 1 teaspoon total). Bake for 15-17 minutes, until golden brown on top.