Preheat the oven to 220°C/200°C fan/425°F/gas mark 7. Line a baking sheet with baking paper.
Place the flour in a large bowl along with the baking powder, nutritional yeast, smoked paprika, chilli powder, garlic granules, thyme and salt and mix to combine.
Add the cold, cubed vegan block butter and the wholegrain mustard. Rub them in using your fingertips until the mixture resembles fine breadcrumbs and no lumps of fat remain.
Stir through the chopped chives then add the milk and stir to form a soft, sticky dough. If it is too dry add a drop more milk. Mix it just enough to form a smooth dough, do not knead it.
Pat the dough out on a floured surface to about 4 cm / 1 ½ inches thick.
Use a floured 6 cm (2 ⅓ in) round cutter to cut out as many scones as you can. Bring together the scraps, pat out the dough again and cut out more scones.
Place the scones spaced apart on the lined baking tray then gently brush the tops with milk.
Bake for about 15 minutes until well risen, golden and firm to the touch. They should sound hollow when tapped on the bottom. Transfer the scones to a cooling rack and allow to cool a little before serving.