Rich, brown, and savorily chocolatey, mixing indigenous ingredients with fruits and spices brought by Spaniards from the far side of the world, mole sauce might be Mexico’s much-older answer to ranch dressing: It’s that irresistible and versatile.

“You can eat mole with vegetables. You can put it on white rice. You can eat it with lobster, crab, steaks, pork chops, or chicken,” ventured Octavio Diaz, executive chef at Agave Uptown, which, thanks to popular demand, recently began retailing 16-ounce bottles of the midnight-dark mole negro that Diaz crafts at the restaurant.

“My parents travel every few months from their home in Healdsburg to buy ingredients for the mole in Oaxaca, where we were born,” Diaz explained. “I can’t reveal what most of those ingredients are, because it’s a secret recipe handed down through the generations, but its key elements include ancho chiles, guajillo chiles, tortillas, tomatoes, cocoa beans, sesame seeds, cinnamon, and Mexican animal crackers.”

Diaz briefly experimented with using more locally sourced versions of some ingredients, “but they didn’t work. It was not the same. The sauce turned out too bitter and too sweet. So, we went back to the roots.”

Three Mexican states—Pueblo, Oaxaca, and Tlaxcala—produce famous mole and claim to be its place of origin, “but Oaxaca’s is the most flavorful. It’s healthier and much more refined,” Diaz asserted. “It’s a celebration.”

Having opened the original Agave Mexican Restaurant and Tequila Bar in Healdsburg in 2010, then opening Agave Uptown last year, Diaz spends four to five days making each batch.

This process includes the roasting of Oaxacan cocoa beans and plantains, “which is where the sweetness comes from,” Diaz said.

Roasted with their skins on, the starchy fruits are then peeled and fried in avocado oil before entering the sauce. Diaz’s version uses no animal fats and is so chocolatey that mole ice cream is a popular item on Agave Uptown’s menu.

“Mole also goes with tuna, with tri-tip, with barbecued meats,” Diaz said. “It’s universal. It goes with anything. My 10- and 11-year-old kids eat it straight, with a spoon.”

Agave Uptown, 2135 Franklin St., Oakland, 510-288-3668, AgaveUptown.com