I fell in love with Penzey's 4S Seasoning Salt when I had it at our daughter's place. It was one of the key ingredients in her Low Brass Eggs. I picked up some 4S at the Penzey's store when we were in the Strip District in Pittsburgh earlier this year. I've just recently learned that there is a Penzey's in Tucson now too, but here I sit over 5,000 miles away with an empty jar.
After reading the ingredients on the jar, this is what I've come up with. The color and taste are not exactly the same, but it's pretty close - good enough to keep me going until I'm back in the land of the big spice store.