Enjoy this crisp, refreshing slaw on its own or pair it with a hearty main. The mellow flavor of raw fennel balances the radishes' spicy bite. Nutty Parmesan brings it all together.
Whisk together oil, lemon juice, and mustard and season with salt and pepper.
Toss dressing with fennel bulb and radishes and adjust seasoning if necessary. Top with Parmesan and fennel fronds.