In a large mixing bowl, combine self-raising flour, instant yeast, and cinnamon. In a saucepan, melt vegan butter with unsweetened soy milk and caster sugar over low heat until lukewarm. Gradually pour this mixture into the dry ingredients, stirring until a sticky dough forms.

Transfer the sticky dough onto a floured surface and knead it for about 5 minutes until it's smooth and springs back when touched. Form the dough into a ball and place it in an oiled bowl. Cover with a clean kitchen towel and let it prove in a warm area for approximately 1 hour, or until it has doubled in size.

Once the dough has risen, gently punch it down to release air and place it on a floured surface. Roll it out into a rectangle about 1/4 inch thick, aiming for an even thickness to ensure consistent baking.

In a small bowl, mix together the smooth Biscoff spread, softened vegan butter, soft light brown sugar, and a touch of cinnamon until you achieve a smooth, creamy consistency. Spread this delightful mixture evenly over the rolled-out dough.

Starting from one edge, carefully roll the dough into a tight log. With a sharp knife or dental floss, slice the roll into 12 equal pieces. Arrange the sliced rolls in a lined baking tin.

Preheat your oven to 180°C (350°F). Brush the tops of the cinnamon rolls with a mixture of melted vegan butter, sugar, and a sprinkle of cinnamon. Bake for about 20 minutes, or until they are golden brown and puffed up.

Once baked, remove the cinnamon rolls from the oven and allow them to cool completely on a wire rack. Meanwhile, mix the vegan cream cheese, remaining Biscoff spread, icing sugar, and a splash of soy milk until creamy. Spread the icing on top of the cooled rolls and sprinkle with crushed Biscoff biscuits.