“Mad Money” host Jim Cramer is bullish on Brooklyn. The CNBC talking head’s latest investment is in a Carroll Gardens Mexican restaurant where he’s even been spotted moonlighting as a waiter, busboy and host.

“Jim likes to relax by decorating [the restaurant], waiting on and busing tables,” said a pal.

“Last night he was seating folks. Jim has a lot of energy.”

We hear the joint’s name, San Miguel, is based on Cramer’s fondness for vacation spot San Miguel de Allende and that his partners include his girlfriend Lisa Detwiler and Regina Myers of nearby Black Mountain Wine House.

We’ll assume from the title of Cramer’s latest book, “Get Rich Carefully,” that he’s also closely looking after the bottom line.