Preheat your oven to 400 °F (205 °C).
Add the cubed sweet potato, olive oil, and salt to a sheet pan and mix until combined.
Roast the potatoes for 30-35 minutes, flipping the sweet potatoes after 15 minutes.
Combine all of the ingredients, except for the buttermilk, in a small bowl. Drizzle in the buttermilk until it's your desired consistency. Chill until ready to serve the salad.
In a large bowl, just before serving, combine all the salad ingredients. Pour the salad dressing over the top. Serve immediately.