It's not a veggie burger. But there's a lot less beef in it than normal.

When Katherine wrote about the "Better Burger Challenge"—a nationwide competition to lessen the impact of our burger habits—I confess I assumed its impact would be limited to farm-to-table restaurants and Whole Foods shoppers. The idea of adding mushrooms or quinoa to your beef burger to lessen its carbon footprint just didn't seem like something your average burger-lover would get into.

Except it's all about taste, apparently.

At least, that's what Fast Company reports that Sonic is saying about its new "Slinger," a burger made with a 70% beef-30% mushroom patty that's going to be rolling out soon for a 60-day trial in select markets, before potentially being added permanently to the menu at Sonic's 3,500+ restaurants. Yes, the burger is healthier, with less fat, lower cholesterol and fewer calories. Yes, it's more sustainable; it takes just 0.7 pounds of CO2 equivalent emissions to produce 1 pound of mushrooms, it takes 12.3 pounds of CO2 equivalent emissions to produce 1 pound of beef (that's according to a study conducted for the Mushroom Council). But the Fast Company article also includes this particular tidbit:

The burger will be marketed for its taste, as a steakhouse-style burger, rather than for its environmental or health benefits. The mushrooms, with a savory flavor, add depth to the burger and make the patty thicker and juicier. Focus groups approved. In an earlier study of another blended recipe, consumers preferred a beef-mushroom mix in tacos to 100% beef.

This is an encouraging sign. There's nothing wrong—of course—with advocating for vegan and vegetarian diets, but it's fair to say that we are a long way off from a world where everyone is eating animal-free. The rise of Reducetarianism, Weekday Vegetarians and other plant-centered eating strategies opens up a much broader avenue to changing dietary behavior.

I've never eaten at Sonic. I doubt I ever will. But I am delighted to see them exploring a lower meat diet too. If you'd like to recreate this at home, there's plenty of recipes on the internet. This half beef, half mushroom burger from the New York Times looks particularly appealing right about now.

If any fast food-eating TreeHuggers (not a contradiction in terms) try the Slinger, please report back and let us know how it was.