Preheat the oven to 180°C / 160°C fan / gas mark 4 and line a 12-hole muffin tin with cupcake cases.
In a large bowl, mix together the plain flour, caster sugar, baking powder, bicarbonate of soda, and salt.
In a jug, whisk together the dairy-free milk, vegetable oil, vanilla extract, and lemon juice.
Pour the wet ingredients into the dry ingredients and stir until smooth and fully combined.
Divide the mixture evenly between the cupcake cases, filling each one about two-thirds full.
Bake for 16–18 minutes until lightly golden and a skewer inserted into the centre comes out clean.
Leave the cupcakes to cool in the tin for a few minutes, then transfer to a wire rack to cool completely.
Top with dairy-free icing if liked once fully cooled.