Toasted Walnut Cinnamon Streusel Scones

Steps

1. Toast the walnuts in a dry skillet over medium heat for 4 to 5 minutes, stirring, until fragrant; cool and chop. Set aside one quarter of the walnuts for the streusel and three quarters for the dough.
2. Preheat the oven to 400°F (200°C) and line a baking sheet with parchment.
3. Make the streusel: in a small bowl, mix one quarter of the brown sugar, one quarter of the cinnamon, the reserved quarter of the walnuts and 25 g of the butter, rubbing with your fingertips into clumps. Chill it.
4. In a large bowl, whisk 360 g of the flour with the remaining three quarters of the brown sugar, the remaining three quarters of the cinnamon, the baking powder, the baking soda and the salt.
5. Cut the remaining butter into the flour mixture with a pastry cutter or your fingertips until it looks like coarse crumbs with some pea-size pieces. Stir in the dough portion of the walnuts.
6. In another bowl, whisk the sour cream, milk, egg and vanilla. Pour into the flour mixture and stir with a fork just until a shaggy dough forms.
7. Dust the counter with the remaining 20 g of flour, turn out the dough and pat it into two 6-inch rounds about 1 inch thick. Cut each round into 6 wedges and set them on the baking sheet.
8. Press the chilled streusel onto the tops of the wedges. Chill the sheet for 15 minutes so the butter firms up.
9. Bake for 18 to 22 minutes, until the scones are golden and a toothpick in the center comes out clean.
10. Cool on a rack for at least 10 minutes before serving.