well, I am not Southern, and it probably shows as I don't have any buttermilk on hand and I probably should. I admit I usually use Betty Crocker cookbook plain baking powder recipe. I use Rumford Brand Aluminum free baking powder. I have no knowlege about the purpose of salt use. If it's for flavor enhancement, then it's ok to omit. If it is necessary to help the rising or something, then it's a quandary if you don't use it. I always use shortening in my biscuits, not butter even when I've had powdered or real buttermilk in a jug.
I'll dust the flour off my fingers and you may take all this with just the hearty handshake offered.
Here's an old recipe off a Saco brand powder buttermilk can. Maybe you can adjust accordingly.
2 cups flour,
2 tsp baking powder,
3 tablespoons powdered buttermilk
1 tsp salt,
1/2 tsp soda,
1 tablespoon sugar.
1/3 cup cold butter
2/3 cup ice water
What I can't remember is did I or did I not reconstitue the buttermilk powder in water before stirring it into the batter. Don't know that this will work if you are using seltzer water without losing the fizz.
Chill some of these ingredients. I never let biscuit dough rest, or if they do, only as long as they are resting on the baking sheet waiting their turn to go in the oven to come out hot for serving. I also knead the dough only to incorporate, not too much.
Make one straight down with a biscuit cutter, no jiggling > this helps them rise evenly in the oven. My biscuits are less than the proscribed inch thick in this recipe. But that's just me. More biscuits = more surface to smear with butter and honey or jam. At Least a half inch, 3/4 inch is my ideal.
Cut in cold butter. Quickly stir in ice water. Pat to 1" thickness, cut into biscuits, bake on greased cookie sheet @400* x 10-12 minutes.
I don't recall Greasing a baking sheet for biscuits in my life. Not cookies either.
Ha ! I just googled up the Saco website-- look at it too. It's different than what I just wrote, but at least they don't grease their pans now either.
SACO Foods Recipes: Saco Buttermilk Biscuits