Fueled by a recent investment from Union Square Hospitality Group, this artisanal ice cream chain is embarking on an East Coast expansion. Salt & Straw, which began as a food cart in Portland, Ore., is known for wild, seasonal ice cream flavors like pear-blue cheese and black tea. USHG’s investment will help the chain build production facilities in Portland and San Francisco, though all ice cream is still made in 3-, 5- and 10-gallon makers.