• Use your favorite unlined pant pattern--from a simple drawstring-waist style to a casual fitted silhouette. Leg width can vary, but a slightly fuller styling (approximately 18" hemline circumference) works well.
  
  
• Cut out the pants according to the instructions on the pattern guidesheet. Serge-finish each side seam. Stitch each side seam, stopping 10" from the lower edge to create a slit; backtack to secure. Press all seam allowances open.
  
• Using a long stitch, topstitch 1/8" from each side of the side seam, stitching across the seam at the slit upper edge (Figure 1). If the chosen pattern has side-seam pockets, stop at the pocket lower edge, then complete the topstitching from pocket upper edge to pant upper edge.
  

• Finish the pants according to the instructions on the pattern guidesheet, omitting a hem finish. Try them on to check the length. Trim as necessary so the pants are the desired length, plus 1".
  
  
• Open the pressed seam allowances on the slit. Serge-finish the hem lower edge, trimming it 1/4". Turn up a double hem and press. Re-fold the slit and topstitch the hem and slit a scant 1/4" from the edge (Figure 2).
  

Figure 2

Topstitch hem and slit 1/4" from edge.

• Stitch a 1/2"-long diagonal buttonhole on the pant front at the slit/hem corner, backing the buttonhole with tear-away stabilizer (Figure 3).
  
  

• Stitch two 1/2"-diameter buttons to the pant back at the slit/hem corner, positioning the first one 3/4" from the slit edge, and the second one 1" from the first, each approximately 1/4" from the hem lower edge (Figure 4).
  
  
• Secure the buttonhole on the first button, leaving the second button exposed as a design detail.