Some of the hidden “gems” I find in SD that hasn’t already been said is “Carne Asada Fries” at the local Roberto’s. It’s not gourmet food by any stretch of imagination, but it’s sure tasty. I find that only So.Cal. Mexican taco shop has this too.
Then there’s the Asian food. Dim Sum is decent price and quite tasty compare to the best of them. There’s an abundant of Vietnamese food from all regions of Vietnam. I find Sushi on the Rocks make the best rolls around. Chinese restaurants with excellent lobster/crab at a very reasonable price; I’d recommend Lee’s Garden and Ly’s Garden. Both are in El Cajon.
We also have Donovan’s who were ranked #1 stake house in the US a few years back.