Need help to ID appropriate yarn to use

Came across a very cute knitted vest in a store and would like to take a stab at making it myself… However, I have no idea what yarn (or maybe a specific knitting technique?) that’ll produce a similar texture to the vest I saw.

Any help in ID’ing the appropriate yarn OR technique would be extremely appreciated! (I prefer to knit with natural fibers)

Here are the images (won’t allow me to post directly in the forum post:

Look for a boucle yarn, Bernat has one, Lion’s Homespun would work, though lots of people hate it; the trick to using it is a large needle or hook (US 11s or size L) and to keep a loose grip on the yarn while you’re working with it. Boucles are textured yarns so you don’t need a fancy stitch, just stockinette and/or garter.

Thanks Suzeeq! I’ll give that a shot.