Preheat oven to 350°F. Grease and flour a 8" round cake pan.
Whisk soy milk and apple cider vinegar in a measuring cup and set aside for a few minutes to curdle.
In a mixing bowl, beat butter, oil and sugar until light and fluffy. Next add pistachio paste and vanilla extract, mix until combined.
Add egg replacer mixture (or eggs) and beat until combined.
Pour in the soy milk and mix well.
Sift flour (s), baking powder and salt into the mixing bowl. Mix until just combined.
Pour into the prepared baking pan and bake for 35~45 minutes or until a toothpick inserted into the center of the cake comes out clean.
Cool the cake for 10 minutes in the pan before inverting it onto a wire rack to cool completely.