Taco Bell® Baja Sauce - Clone recipe

Taco Bell®'s Baja Sauce, also known as Creamy Pepper Jack Sauce, is used in a number of their food products.  It's pretty tasty, so why not make it yourself.  I took ideas from some online recipes and adjusted the taste somewhat, but this one is for Amanda.  This recipe is from http://cookingventures.blogspot.com/.

INGREDIENTS

1/3 c pepper jack cheese, freshly grated, the finer the better
2 tbsp Parmesan cheese, freshly grated very finely
1/2 tsp cornstarch
1/4 tsp onion powder
1/4 tsp garlic powder
1/8 tsp  salt)
2 tsp corn syrup
1 tsp Dijon mustard
1 medium to large jalapeno pepper (seeds and ribs removed), very finely diced
1 Tbsp dry butermilk
1/2 c evaporated milk
5 TBSP vinegar, divided use
1 TBSP drained pimentos or roasted red peppers, diced
1/16 tsp (just a pinch) cayenne
¼- ½ cup mayonnaise (4-8 tablespoons) depending on desired consistency

METHOD

Combine the cheeses and cornstarch in a small bowl and mix well. Set aside.

In a small saucepan, whisk together the onion powder, garlic powder, salt, corn syrup, mustard, jalapeno, dry buttermilk, evaporated milk, and only 4 tablespoons of the vinegar. Whisk the mixture until the buttermilk powder has dissolved. Turn on the heat to medium and whisk often while the mixture is heating. Bring the mixture to a good simmer and, VERY IMPORTANTLY, remove the sauce pan completely from the heat. 

VERY slowly whisk in the mixed cheeses, about a tablespoon at a time. Briskly whisk for at least 1 minute after each addition, making sure the cheese have completely melted. If you add the cheese while still on the heat, you will cause the proteins in the cheeses to form gritty little particles that will ruin the texture of the sauce.

Add the cheese mixture to a blender with the pimentos/red peppers. Whiz the mixture until the jalapenos and pimentos are very finely chopped and the mixture is smooth. Scoop the mixture into a seal-able bowl and allow it to come to room temperature on your kitchen counter.

When the cheese mixture has cooled completely, add the remaining tablespoon of vinegar, the cayenne pepper and sufficient mayonnaise to bring it to the consistency you desire, then stir to combine. Seal and put the mixture in the refrigerator for at least 4 hours to allow the flavors to meld and the sauce to firm up.