Step 1: Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper to ensure your roasted root veggie tacos with avocado don't stick.
Step 2: In a large mixing bowl, combine the diced sweet potatoes, carrots, and parsnips. Drizzle with olive oil and sprinkle with cumin, smoked paprika, and salt.
Step 3: Toss the vegetables until they are evenly coated in the oil and spices, which is crucial for the flavor profile of the roasted root veggie tacos with avocado.
Step 4: Spread the vegetables in a single layer on the prepared baking sheet, ensuring they have enough space to roast properly.
Step 5: Roast in the oven for 25-30 minutes, or until the vegetables are tender and have developed caramelized edges for the roasted root veggie tacos with avocado.
Step 6: While the vegetables roast, warm your corn tortillas in a dry skillet over medium heat for about 30 seconds per side until pliable.
Step 7: To assemble the roasted root veggie tacos with avocado, place a generous spoonful of the roasted vegetables in the center of each warm tortilla.
Step 8: Top each taco with slices of fresh avocado, a sprinkle of cilantro, and a squeeze of lime juice before serving your delicious roasted root veggie tacos with avocado.