In a jar, combine all the spices, romano cheese and sugar.
Add the hot water, stir and let sit a couple minutes to rehydrate the dried spices.
Add the buttermilk and mayo and whisk together.
Keep refrigerated until ready to serve.
The best source I've found for dried romano cheese is the Spice and Tea Exchange. Their romano doesn't contain any weird ingredients and it's always fresh. You'll need roughly 1.2 ounces to make a single recipe.
Prep your spices in jars for quick weeknight dressings. The recipe makes a little over one cup, so choose a jar with room for whisking.