Melt butter in a small saucepan over medium heat. Add minced garlic and cook for 30 seconds until fragrant but not browned. You want to smell the garlic, not see it turn golden.

Whisk in the flour and cook for 1 minute, stirring constantly, until the mixture looks like wet sand and no raw flour smell remains. This prevents a pasty taste in your finished sauce.

Slowly pour in the warm milk while whisking vigorously to prevent lumps. Add the cream and continue whisking until the mixture is smooth. The warmth of the milk helps the roux incorporate without clumping.

Cook over medium-low heat, whisking occasionally, for 3 to 4 minutes until the sauce thickens enough to coat the back of a spoon. It should look like thin pancake batter - it will thicken more as it cools.

Remove from heat and immediately stir in the Parmesan, oregano, red pepper flakes if using, salt, and pepper. Stir until the cheese is fully melted and the sauce is silky. Taste and adjust salt as needed.

Let the sauce cool for 5 to 10 minutes before spreading on pizza dough. It should be warm but not hot - this prevents it from sliding off the dough and helps it set into a creamy layer during baking.