Leave out the first salt if using seasoned salt (My note) works OK with 1/2 tb lemon juice in milk thickened with extra milk powder to make 1/2 cup. Sprinkled salt did not stick very well, suggest mixing in the desired amount of regular salt. Spices may mix more evenly if combined first with the flour.
Preheat oven to 400 F. Sift together the flour, sugar, salt and baking soda into a bowl or food processor. Cut in the butter. Add the sour ceam and salt or seasoning. Mix to a soft dough.
Roll out PAPER-THIN on a floured board. Cut in 1 1/2" squares or shapes and sprinkle with salt (see note). Bake on ungreased baking sheet about 5 min. Remove the thin pieces that brown first if necessary and give the other pieces a bit longer to brown. Turn off heat and crisp in the oven.
Makes about 3 small cookie sheets of "crackers" almost touching or may be cooked in larger sheets to break up after cooking. May be rolled between sheets of wax paper 1/4 to 1/2 of the dough at a time.
Keep for snacking in an air tight jar. Suggestion - divide the dough and the spices in thirds. Mix and bake the first pan and taste so that seasoning or salt can be adjusted. OR make some spicy and some just salted and cut them different shapes so you know which are which.