Preheat oven to 210C/190C Fan/Gas 6. Line 2 large baking tray.
In a food processor, or using your hands, combine the flour, sugar and baking powder. Then add the butter and rub in, until the mixture resembles breadcrumbs.
Add the coffee to the milk and mix together before adding to the dough with the vanilla extract. Use a knife to combine until the mixture forms a shaggy dough. Then add the chopped walnuts.
Tip the mixture onto a baking sheet, press out to just taller than an inch and cut out about 6 large circular scones - use a cookie cutter!
Place 3 to each tray and brush over a little milk and sprinkle over some sugar. Bake for 18-20mins, until golden brown.
Let cool on a wire rack. Once cool, make the glaze by combining the icing sugar and coffee, plus about 2 tsp water in a small bowl. It should be pourable/runny enough to drizzle.
Use a teaspoon to drizzle the glaze over the scones. Give them 10 mins to set before serving!