Time to change lines of business. "We're a taco shop, but you can buy weed here in compliamce with local laws. Sorry if you receipt just says TACOS no matter what you buy. We're working on that."
Basically what dispensaries in Washington, DC do. Everything is a "donation" or an "art purchase" and the pot is a "gift". Total nonsense, but it mostly works, because DC intends to legalize recreational marijuana sales, and Congress isn't letting it happen. So it seems like enforcement is just lax.
What has worked in some states is the 'gift pot' strategy. You sell them a vastly overpriced taco and they get a gift of weed along with the snack. Generally the states get upset about this and close the loophole.