For the Cashew Sour Cream:

1. To make the cashew sour cream: Place the cashews in a medium-size bowl fitted with a lid. Cover with filtered water and give it all a stir. Cover the bowl with the lid and soak overnight at room temperature.
2. The next day, drain and rinse the cashews. Transfer to a high-speed blender with the rest of the ingredients and 2 tablespoons (30 ml) of water. Blend on high until completely smooth. Add more water as needed, 1 tablespoon (15 ml) at a time, but don’t let it get too liquid-y.
3. Transfer to a medium-size bowl fitted with a lid and let stand at room temperature overnight so it becomes sour. Once ready, transfer to the refrigerator for another 2 days to allow a slower souring process to develop. After that, the sour cream is ready for use.

For the Scones:

1. Preheat the oven to 425°F (200°C, or gas mark 7). Line a baking sheet with a silicone baking mat.
2. In a medium-size bowl, whisk to combine the flour, baking powder, salt, sugar, and pepper. Transfer to a food processor. Add the butter cubes and pulse a couple of times to distribute. Add the sour cream and pulse a few times just to form a dough. Add the scallions and pulse just to distribute. Transfer the dough to the baking mat and quickly shape it into an 8 × 4-inch (20 × 10 cm) log. Cut the log into 4 equal scones, leaving a good 11/2 inches (4 cm) between the scones.
3. Bake for 22 to 24 minutes until golden brown.
4. Store in an airtight container at room temperature, or in the refrigerator, for up to 2 days. Reheat leftovers in a 325°F (170°C, or gas mark 3) oven for 8 to 10 minutes.