1-First Step: Prep the oven and pan Preheat the oven to 425 degrees Fahrenheit. Line a baking tray with parchment paper so cleanup stays simple and the vegetables do not stick. This high heat helps the potatoes and cauliflower brown instead of steaming.

2-Second Step: Prepare the vegetables Quarter the new potatoes, cut the cauliflower into florets if needed, and slice the leeks into half moons. Trim the asparagus and cut it into 2-inch pieces. Keeping the pieces similar in size helps the vegetables roast evenly.

3-Third Step: Arrange the first vegetables Place the potatoes, cauliflower, and leeks on the lined tray in a single layer. Drizzle with 1 to 2 tablespoons avocado oil or olive oil, then season generously with sea salt and black pepper. Toss lightly so the oil coats everything well. If you like a more herb-forward flavor, you can add a little fresh thyme now.

4-Fourth Step: Roast the vegetables Slide the tray into the oven and roast for 25 minutes. During this time, the potatoes start to soften and the cauliflower begins to develop golden edges. The leeks also turn sweet and tender, which gives the dish a mellow base flavor.

5-Fifth Step: Add the asparagus and lemon After 25 minutes, take the tray out and add the chopped asparagus. Toss it gently with the roasted vegetables so it can pick up some of the oil and seasoning. Then place the thin lemon slices on top. Return the tray to the oven for another 10 minutes. If your asparagus is very thin, keep a close eye on it during the last 10 minutes so it stays tender and bright.

6-Final Step: Finish and serve When the vegetables are tender and lightly browned, remove the tray from the oven. Scatter fresh herbs over the top if you want extra color and flavor. Italian parsley, fresh dill, spring onions, or fresh thyme all work well. Serve hot as a side dish, or turn it into a bigger meal with grains, eggs, chicken, or fish.