Biscoff Vegan Traybake Cake

• 250 ml soy milk unsweetened
• 2 Teaspoons apple cider vinegar (or lemon juice)
• 280 g self-raising flour
• ½ Teaspoon bicarbonate of soda
• ½ Teaspoon cinnamon
• 160 g caster sugar
• 140 g vegan margarine melted
• 1 Teaspoon vanilla extract
• 6 Biscoff biscuits crushed into crumbs

For the Biscoff buttercream:

• 100 g vegan margarine
• 100 g Biscoff spread smooth
• 200 g icing sugar

To top:

• Extra Biscoff biscuits