Start by shredding the green cabbage and red cabbage. I find the best way to do this is to use a mandolin slicer set on a fine setting. Make sure to use the safety guard to protect your fingers! If you don’t have a mandolin, you can carefully use a large chef’s knife to thinly slice the cabbages. The goal is to have uniform, thin shreds that will mix well with the other ingredients.
Next, take your carrots and shred them using a box grater. This will give your coleslaw the necessary crunch and a hint of sweetness. You can also julienne the carrots if you prefer longer pieces.
Set out a large mixing bowl and add both kinds of shredded cabbage along with the shredded carrots. Toss them together gently to combine. This is where the vibrant colors of the coleslaw really start to shine, and you can already see how appealing it will look!
In a separate bowl or measuring pitcher, combine the mayonnaise, lemon juice, rice vinegar, sugar, salt, black pepper, celery seeds, and onion powder. Whisk everything together until smooth. This dressing is the heart of your coleslaw, and it should be creamy with a nice balance of tanginess and sweetness.
Pour the dressing over the coleslaw mix and toss well to fully coat the vegetables. Make sure every shred of cabbage and carrot is covered with the creamy dressing. This step is crucial for flavor, so take your time to mix thoroughly.
Once everything is well combined, cover the mixing bowl with plastic wrap or a lid and refrigerate for at least 30 minutes. This allows the flavors to meld together beautifully and gives the coleslaw a chance to chill, making it even more refreshing.