PREHEAT OVEN TO 425
Line two large baking sheets with parchment paper
FOR THE ASPARAGUS:
Place the prepared asparagus on one of the lined baking sheets. Drizzle with 2 tablespoons of the olive oil, then sprinkle with a little salt and pepper. Set aside.
FOR THE RADISH AND FENNEL:
Combine the prepared radishes in a large bowl with the watermelon radish, purple daikon, fennel and shallots.
Add the other 2 tablespoons of olive oil, or a little more if needed, and toss to completely coat the vegetables with the oil.
Add a teaspoon of freshly ground pepper and 1 1/2 teaspoons of kosher or sea salt. Toss together to combine.
Put the radish/fennel mixture on the second parchment-lined baking sheet, and spread the mixture out as evenly as possible for even roasting. Place the tray on the lower rack of the oven for 30 minutes. Remove from oven and gently turn the vegetables over with a spatula. Return the radish/fennel tray back to the oven on the lower rackNow put the baking sheet of asparagus in the oven too, on the middle middle oven rack - and roast both trays for about 15 minutes. Remove just the baking sheet with the radish/fennel mixture, and gently turn the mixture over once more with a spatula. This is to make sure the vegetables roast evenly. Sprinkle the radish/fennel mixture with the Parmesan cheese and a little more olive oil, then return the pan to the oven for another 10 minutes.Remove both trays from oven for serving.
NOTE: The total roasting time is approximately 55 minutes for the radish/fennel mixture, but can vary depending on your oven. The vegetables are done when they are fork tender and a little blistered in appearance. Note that the total cooking time for the asparagus is about 20 minutes, which is why the cooking times are staggered so they come out of the oven at the same time.
To Serve, transfer the asparagus to the serving tray or individual plates, then top with the radish and fennel mixture and a little more Parmesan cheese if you like. Use some of the fennel leaves for garnish, if desired. Serve with the vinaigrette alongside to drizzle over the top.
MAKE THE VINAIGRETTE
Combine all of the vinaigrette ingredients in a small jar with a lid and shake to combine.
Taste and adjust with a bit more salt, if needed.