Bring the ribbon up to the top, make sure you have a nice straight line and tuck underneath the enveloped shoulder seam. Fold the ribbon under 1/4" along the top edge and pin in place. Sew using a zigzag stitch to secure. Repeat for opposite side of onesie.
To make the bowtie, use the fat quarter of fabric. I like a nice thick bow tie that holds its shape, which requires a lot of folds. Cut two rectangles from the fat quarter: one at 18” x 13” for the bowtie; one at 8” x 4” for the bowtie center.
Wrap the bowtie center around the middle of the bow tie, and squeeze it together in the back. Sew the back bowtie center together very carefully where the two sides meet. Use a zipper foot if you have one or sew by hand to secure.
Following the directions on the sew-on snaps package, secure the two ends to the back of the bowtie, and the opposite ends to the top center of the onesie. It is important to sew two snaps onto the onesie to ensure that the bowtie stays in place.