Combine all ingredients together in a small saucepan, on medium-low heat.
Whisk everything together until it is all well combined and bring the mixture to a simmer.
Partially cover the saucepan (Note 1) and let the sauce simmer for 10-15 minutes, stirring occasionally, until it has thickened. (Note 2)
Let the sauce cool to room temperature before placing in the fridge to cool completely. (Note 3)
Use as desired on pizzas.
Notes
Partially covering the saucepan allows for steam to escape and helps prevent the sauce splattering all over the place.
The easiest way to tell if the sauce has thickened enough is to scrape a wooden spoon along the bottom of the bottom of the saucepan. If the sauce holds it's shape and doesn't immediately cover the exposed saucepan then it is ready.
The sauce can be used immediately but I find that letting the sauce cool completely in the fridge allows for the tanginess to mellow out a bit, which I enjoy more.