Preheat the oven to 400℉. Add the purple potatoes, eggplant, and beets in a single layer onto a lined baking sheet. Drizzle a little olive oil and sprinkle a pinch of salt. Roast for 22-25 minutes, until tender. Remove and let it cool.
In the meantime, cook the beluga lentils in about two and a half cups water over a medium flame for about 25 minutes just until tender and not mushy. Remove from the flame, drain, and set aside.
While the lentil coks, make the vinaigrette by adding all the listed under "for the purple basil flower vinaigrette". Whisk thoroughly.
Add all the veggies and lentils to a bowl. Drizzle the vinaigrette and mix well.
Transfer to a serving plate and serve as such or with bread or with chips.