Heat the oven to 180C.
Add the muffin liners into the muffin tin and set aside.
In a bowl, mix the flour, sugar, baking powder and lemon zest. Add the oil, vanilla, lemon juice and soy milk, then mix until smooth.
Pour the mixture into the tin, in each muffin liner.
Bake for 25 minutes. Test with a toothpick. Insert it in the middle of a muffin and if it comes out clean, they're ready. Otherwise, let them bake for a couple more minutes.
Let them cool in the tin for 10 minutes, then remove and transfer the muffins on a rack to cool.
For the icing, add the powdered sugar and turmeric powder into a small bowl. Mix in lemon juice. Mix until incorporated and sticky. Top each vegan lemon muffin with a teaspoon of icing.