I have been marinading a Tri Tip for two days now and it's going to be dinner tonight. The only thing different that I did this time, that I took the marinade, put it into a pot and brought it to a boil. After it boiled for about five minutes, I reduced the heat to low and just let it simmer to reduce the liquid. After an hour, I added about one inch of butter to the mixture and continued to stir and reduce the marinade even further. Then I added one tablespoon of corn starch mixed with the reduced marinade mixture. This thicken everything up. It came out like an upscale A1 sauce which I poured on the side to dip the Tri Tip in. It was very, very good.
The only thing about having a dinner like this, is that I have a craving for sweets about 2 hours later. I sure could go for a chocolate cannoli.
Here's a video of the process.
Ed