In a small saucepan over medium-low heat, melt the butter. Whisk in the garlic and heat until fragrant, about 1 minute. Whisk in cornstarch a little at a time so you don't get any lumps.
Pour in half-and-half and whisk until combined. Reduce heat to low and simmer; stirring often, for 3-5 minutes or until sauce is thickened to your liking. (Cook a few more minutes if your sauce is too thin. If your sauce is too thick, add a bit more half-and-half.)
Turn off heat and add Parmesan cheese. Whisk until melted and smooth.
Stir in Italian seasoning, sea salt, black pepper, oregano and onion powder.
Spread on your pizza crust immediately. If you do not plan to use the sauce right away, allow it to cool before placing in an airtight container into the refrigerator.
