Step 1

In a medium sized saucepan, melt the butter gently over a low heat.

Step 2

Now, add the sourdough starter (or discard) and around 50g of milk (a good splash) and gently loosen the sourdough starter with a whisk so that the butter, sourdough starter and milk form a loose paste (this is like a roux but with a slightly different technique because you're using sourdough starter instead of flour).

Step 3

Now, add the milk in small batches while continuing to whisk the white pizza sauce.

Step 4

Once all the milk has been added and the sauce is starting to thicken, add the minced garlic, crumbled sharp cheddar, salt, pepper and onion powder.

Step 5

Continue to whisk until the cheese is completely melted and the sauce is thick and smooth.

Step 6

Once the sauce is thickened to your liking, remove from the heat and transfer to a container or bowl. Allow to cool before adding to your pizza base.