Say you were going go make a 6 x 8 mug rug (finished size) - cut the fabrics 6.5 x 8.5 - cut the batting 6 x 8 -
barely catch the batting to one layer - or even baste or glue the batting to one layer - then sew right sides together of the fabrics - and then do the "birthing" method to turn it right side out.
This way, you would have the bulk of the seam allowances, but only one layer of batting at the seam lines.