The strip mall doesn’t seem promising, but the fleet of trucks outside Brent’s, ready to deliver the deli’s provisions, proclaims it a favorite. From the moment you enter, you can’t help feeling the joyous abandon. Groups wait by the door, the to-go counter is humming, and in the galley kitchen a scrum of countermen slice, pile, and schmear as they work through the tickets on the order wheel. No deli so perfectly combines the quality of the food with that of the atmosphere. Family patriarch Ron Peskin, or his son Brent, or son-in-law Marc, bounce from booth to booth. On the walls, pride of place is reserved for a framed ceremonial fireman’s ax given to the Peskin family in recognition of the number of emergency workers it fed after the Northridge earthquake. All this amounts to an authenticity that the newer location in Westlake Village doesn’t share. The whitefish salad here has a wondrous texture: part flaky, part creamy, begging for a bagel. Reubens are a specialty, and while the turkey and grilled knockwurst varieties are intensely satisfying, the black pastrami Reuben with hot sauerkraut and Russian dressing on grilled rye is a definitive sandwich. The Ortega brisket melt, with roasted chiles, grilled onions, and juicy layered meat, offers the magnificence and heft of a Reuben in burnished tones.