Upon entering the organic, gluten-free, vegan and kosher eatery in Rittenhouse, I wondered whether I had mistakenly stepped into a greenhouse—an apt vibe given the potted plants, an abundance of natural light and the array of fresh soups, salads, and wraps on display. I felt skinnier just standing there.

The slow Friday afternoon gave us ample space to get comfortable at one of the café-style tables. Our meal began with a number of pre–made salads that varied negligibly in taste. The most exciting part of the Kale Avocado & Kraut salad ($12.50) was the dressing: a carrot-ginger purée with the consistency of applesauce. I disregarded everything else, including the tofu reminiscent of a cold McNugget.

The crunchy spiced beans and shiitake crisps made the Sunflower Caesar Salad ($12.50) much less mediocre. Although the dressing was a bit too salty, using sunflower seeds to achieve the same creaminess of standard Caesar dressing deserves praise.

To the owner, Andrea Kyan, this kind of plant–based eating has always been a “no–brainer.”

Growing up, the vegan of eight years “felt very privileged always being around home-cooked, very delicious, nutritious food”—an upbringing that inspired her to open the restaurant. “I’m doing this for public health reasons,” she explains. If all goes well, Ms. Kyan hopes to use the profits to start a foundation that educates people on food policy.

Traces of her Chinese-Burmese background appear in dishes like the Garden Daikon Pad Thai ($12.50), a warm dish full of flavor and color. The edamame was a bit soggy, but the kiwi added a great kick to the savory noodles.

“Most people think health is a form of deprivation and it’s not,” Ms. Kyan insisted—a sentiment we were not fully convinced of until the friendly staff served us two desserts. Between the flaky crust and the chocolate drizzle, the Pumpkin Tart ($8.00) was definitely worthy of my grandmother’s Thanksgiving. After devouring that, my date and I fought over the Banana Cream Tart ($8.00)—a pastry layered with banana, peanut butter and a dark chocolate ganache that redeemed the meh-ness of the earlier dishes. Sadly I finished it off with the overly citric Bangkok juice—a blend of pineapple, lime, mint, and lemongrass that made me feel like someone had just waxed my nose hairs.

Overall, your appreciation of P.S. & Co. depends on your diet. If you’re a health nut, you’ll rejoice in the juices. If you’re a carnivore, you’ll leave a little poorer and still a little hungry—but hey, at least you’ll have some kale stuck in your teeth for later.