Shred the cabbage into thin 1/8-inch strips using a mandoline or sharp knife—this thickness is crucial for the best crunch and texture. Slice the scallions into thin rounds, separating white and light green parts from the dark green tops, and roughly chop the cilantro. Set all prepared vegetables aside in separate piles.

In a large bowl, whisk together the sour cream and mayonnaise until smooth and combined. Add the lime zest, lime juice, salt, cumin, and honey, whisking until the dressing is fully emulsified and the spices are evenly distributed. Taste and adjust seasoning as needed—I like to add a touch more lime juice if the dressing needs extra brightness and acidity to cut through the richness of the cream.

Add the shredded cabbage, scallion whites and light green parts, and cilantro to the bowl with the dressing. Gently toss everything together until the vegetables are evenly coated, being careful not to crush the cabbage. Let the slaw sit at room temperature for about 1 hour—this allows the cabbage to soften slightly while staying crisp, and the flavors to meld beautifully. I find that this resting time really brings out the lime and cumin flavors throughout the slaw.

Give the slaw a final gentle toss to redistribute any dressing that may have settled. Top with the reserved dark green scallion tops for a fresh pop of color and a hint of onion bite. Serve immediately alongside your tacos, adjusting the seasoning one last time if needed.