vanilla frosting

2-3 tbsp whole milk or soy milk, at room temperature
1-2 tbsp vanilla extract, at room temperature
1 tbsp lemon juice, freshly squeezed at room temperature
1/2tsp lemon zest, finely grated
1 tbsp margarine, at room temperature
2- 4 c confectioner's sugar

The above measurements are approximate.
In a small bowl, whisk together the milk, vanilla, lemon juice, and zest. Pour in some powdered sugar. Add the milk mixture in 3 batches, waiting for each batch to be fully incorporated before adding the next (scrape the bowl down occasionally). Mix briefly until fluffy, and of the consistency you desire. Use more milk or sugar to get a larger batch, and a consistency you desire. Sugar will thicken, and a little milk will go to loosen. The margarine will allow a creamy consistency. May be stored, covered, in the refrigerator for 3 days.