Start by preheating your oven to 425°F and line two baking trays with parchment paper. This temperature helps vegetables roast quickly while developing crispy edges. Preparing the trays first also saves time later.
Bring a large pot of salted water to a boil and add the baby potatoes. Let them cook for about 10 minutes or until they become fork-tender. Boiling first ensures the potatoes will smash easily before roasting.
Drain the potatoes and place them on a lined baking tray. Use a fork or flat measuring cup to gently smash them. Drizzle with oil, season with salt and pepper, and roast for 20 minutes before flipping and roasting another 10–15 minutes until crispy.
On the second tray, spread the shredded Brussels sprouts and sliced shallots. Season with salt and pepper and drizzle with oil. Roast for about 15 minutes, then add shredded kale and bake another 5 minutes until slightly wilted.
While the vegetables roast, mix the dressing ingredients in a jar. Combine garlic, vinegar, black pepper, chili flakes, white pepper, mustard, lemon zest, lemon juice, salt, maple syrup, and olive oil. Shake well until the dressing becomes smooth and creamy.
Transfer the crispy potatoes to the tray with the roasted Brussels sprouts and kale. Add edamame, chives, and some of the dressing. Toss everything gently so the dressing coats all the ingredients evenly.
Divide the salad into bowls and drizzle with extra lemon pepper dressing if desired. You can serve it warm right away or enjoy it chilled later for a quick meal.