Sure you can make 4 HST at a time. Put 2 pieces Right Sides Together and sew all the way around the outside with a 1/4" seam. Cut diagonally both ways and you have 4 HST. The edges will be on the bias, but you can starch them to hold their shape through your sewing process. I think MSQC has a tutorial on this method and I think you can do a search on QB for the size of square to start with so you will have the correct size finished HST block. Good Luck.