Heat the oven to 180℃/160℃ fan/350℉/gas mark 4. Line a 2lb loaf tin with baking parchment.
Melt the butter, pour it into a large bowl and set aside until it has cooled to just barely warm, then mix in the oil, lemon zest, cardamom, salt and bicarbonate of soda.
120 g (½ cup) vegan block butter, 41 g (3 Tablespoons oil (I use olive), finely grated zest of 2 lemons, 1 ¼ teaspoons freshly ground cardamom*, ¼ teaspoon salt, ¼ teaspoon bicarbonate of soda (baking soda)
Add the flour and stir with a spatula until it is fully coated in the butter mixture.
300 g (2 ½ cups) self-raising flour
Stir in the yogurt and sugar to make a thick batter, then add the milk, lemon juice and vanilla extract. Mix to form a smooth, lump free batter, you may find it easier to switch to a balloon whisk at this point.
160 g (⅔ cup) vegan Greek style soya yogurt, 250 g (1 + ¼ cups) caster or granulated sugar, 90 g (6 Tablespoons) unsweetened non-dairy milk (I use soy), 30 g (2 Tablespoons) lemon juice, 2 teaspoons vanilla extract
Pour the batter into the tin and level the top. Dip a butter knife in oil and draw a line down the centre of the batter - this ensures that you will get an even crack down the middle of the loaf.
Bake for 55-60 minutes until well risen, golden brown, and a skewer inserted into the centre comes out clean. You may need to cover the top of the cake with foil partway through baking to prevent it from browning too much.
Leave to cool in the tin for 10 minutes then turn it out onto a wire rack to cool completely.
To make the glaze, sift the icing sugar into a bowl and gradually stir in enough lemon juice to make a smooth, thick but spoonable icing. Pour the glaze over the cake, making sure that it gets an even coating, you may want to place a tray under the cake to catch any drips. Allow to set before slicing.
150 g (1 + ¼ cups) icing (powdered) sugar, juice of 1 lemon