Whole Foods just backed a tiny sandwich chain no one has heard of - and now it's planning a huge expansion

Whole Foods just backed a tiny Los Angeles sandwich chain called Mendocino Farms.

The grocery chain took a minority stake in the restaurant, which has only 11 locations and is now planning a massive expansion with the investment, Nation's Restaurant News reports.

In addition to opening new standalone restaurants, Mendocino will also open restaurants inside new and existing Whole Foods stores, according to NRN.

The restaurants will serve the sandwich chain's full menu and be wholly operated by Mendocino.

The menu includes items like "not so fried" chicken, spicy lemongrass steak banh mi, house smoked chicken and street corn torta, and prosciutto and free range chicken.

"Mendocino Farms is one of the best sandwich and salad concepts coming out of Southern California and we believe it's one of the top emerging restaurant brands in the country," Whole Foods Executive Vice President of Operations David Lannon said in a statement.

Mendocino Farms is a fast-casual concept featuring organic, locally-sourced ingredients on freshly baked bread.

Prices are comparable to Chipotle, with customers paying an average of $12.50 for a meal, according to NRN.

The average unit brings in about $3.2 million in revenue.

The restaurants' interiors feature chalkboard walls and wood and stainless steel accents, with lit-up signs that read "EAT HAPPY." Green turf covers parts of the ceiling, chairs, and walls in some restaurants.

Some restaurants also feature foosball tables.

Whole Foods will likely add Mendocino units to its new cheaper store concept, called 365 by Whole Foods market, according to NRN.

The grocery chain is planning to opening its first five 365 stores next year, including one in the Los Angeles neighborhood of Silver Lake. The 365 stores will be targeted to millennials, according to Whole Foods executives.

Here's a vegan wrap:

This sandwich features thick-cut turkey, tomato, avocado, smoked Gouda, chili aioli and jalapeno relish.

The restaurant also smokes its own barbecue. This sandwich features pulled pork that has been smoked for eight hours.

The chain features hearty salads like this one with cotija cheese, quinoa, grape tomatoes, avocado, and tortilla chips.