Set the oven to 425°.
In a medium sized bowl, toss the parsnips and cauliflower together with 2 tablespoons of olive oil, salt, and pepper.
Arrange the parsnips and cauliflower on a half sheet pan and bake for 25-30 minutes.
In a large pot over medium heat, add the last tablespoon of oil and heat until warm. Add the onion and cook, stirring occasionally, until translucent 5 to 7 minutes. Add the garlic and cook for another 2 minutes.
Add the roasted parsnips and cauliflower, vegetable broth, and two cups of water to the pot.
Bring the mixture to a boil and then lower the heat and simmer, covered, for 15 minutes.
Add the miso and stir until fully dissolved.
Make the parsnip ribbons: In a medium size saucepan with high sides, heat the oil over high heat until the oil begins to ripple.
Gently place a handful of the parsnip ribbons into the oil and cook, stirring occasionally, for 30 seconds to a minute or until golden brown.
Remove from the oil and place onto a plate lined with paper-towel. Sprinkle with salt. Repeat until all the ribbons have been cooked.
After the soup has been simmering for about 15 minutes, remove it from the heat.
Using an immersion blender, puree the soup until smooth (or puree in batches in a blender and return to the pot).
Stir in the lemon zest and juice just before serving.
Sprinkle with chili powder and then top with the parsnip ribbons. Garnish with fresh parsley and enjoy!