Preheat your oven to 180°C (350°F). Combine plain flour, icing sugar, and salt in a mixing bowl. Rub in vegan butter until coarse crumbs. Gradually add dairy-free milk to form a smooth dough. Press into tart shells and chill for 30 minutes.

Bake for 15 minutes, remove baking beans, then return for another 5 minutes until golden. Cool on a wire rack.

In a saucepan, combine caster sugar and water, heating until sugar dissolves. Boil until amber, about 8-10 minutes. Stir in coconut milk, vegan butter, and salt. Pour into tart shells and refrigerate for 1 hour.

Whip aquafaba with cream of tartar until soft peaks form. Gradually add caster sugar, whip until stiff peaks and glossy. Mix in vanilla extract.

Pipe meringue onto tarts in ghost shapes. Toast lightly if desired. Decorate with black food gel or melted chocolate.

Chill assembled tarts for 30 minutes before serving on a Halloween platter.