Finely shred the cabbages. Peel and grate carrots on large holes of a box grater. Add to a large bowl and toss to combine.
Zest limes to get 1 teaspoon zest, then juice to get 1/4 cup fresh lime juice.
Add lime juice, zest, garlic, cilantro, jalapeño, mayo, and sour cream to a blender or mini food processor. Season with salt and pepper (I add 1/2 tsp salt and 1/4 tsp pepper)
Blend until completely smooth and creamy.
Pour dressing over the slaw and toss until everything is well coated. Taste and adjust salt and pepper as needed.
Optional: Let sit 15 to 30 minutes for best flavor, then toss again and serve.
Video
Notes
Note 1: When handling jalapeños, wear gloves to avoid burning your skin. Wash your hands immediately after. Cut the jalapeño in half, remove seeds, and coarsely chop. For a spicier sauce, add more jalapeño gradually. Note: wrinkly jalapeños are spicier than smooth ones.Storage: Store Mexican slaw in an airtight container in the fridge for up to 2 to 3 days. It’s best the same day for the freshest, crisp texture. Give it a quick toss before serving, and for the best results, store the slaw and dressing separately and combine just before eating.