Whisk together the melted butter, treacle, light brown soft sugar and milk in a bowl until smooth.
90 g (6 Tablespoons) vegan block butter, 90 g (4 ½ Tablespoons) black treacle or molasses, 120 g (½ cup + 1 ½ Tablespoons) light or dark brown soft sugar, 30 g (2 Tablespoons) unsweetened non-dairy milk (I use soy)
Mix in the baking powder, bicarbonate of soda, salt, ginger, cinnamon and cloves, followed by the flour. Stir until no dry patches remain.
¾ teaspoon bicarbonate of soda (baking soda), ½ teaspoon baking powder, ¼ teaspoon fine table salt, 3 teaspoons ground ginger, 2 teaspoons ground cinnamon, ¼ teaspoon ground cloves, 280 g (1 ½ cups) plain (all-purpose) flour
Cover the bowl and chill the dough in the fridge for about 1 hour.
Preheat the oven to 180℃/160℃ fan/350℉/gas mark 4. Line two baking sheets with baking parchment. Place the caster/graulated sugar in one small bowl, and the icing/powdered sugar in another.
50 g (¼ cup) caster or granulated sugar, 50 g (½ cup) icing (powdered) sugar
Divide the chilled dough into 16 portions, about a heaped Tablespoon each, and roll them into balls.
Roll the balls first in the caster/granulated sugar, giving them a light coating, and then in the icing/powdered sugar, making sure that they have a thick, even coating.
Place the cookies spaced apart on the lined baking sheets and bake for 12-18 minutes until firm around the edges but still slightly wet looking in the centre. Bake them for the shorter amount of time if you prefer them slightly gooey in the centre, and the longer amount of time if you prefer a firmer textured cookie.
Allow the cookies to cool on the baking sheets for 5-10 minutes, then gently transfer them to a wire rack to cool completely.