Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Peel and cut the sweet potatoes into 1-inch cubes, then place them on the baking sheet.
Drizzle the sweet potatoes with olive oil and sprinkle with sea salt and black pepper, tossing to coat evenly.
Roast the potatoes for 15 minutes until they begin to soften.
In a small bowl, whisk together the maple syrup, apple cider vinegar, dijon mustard, and ground cinnamon to create the glaze.
Move the potatoes to the outer edges of the pan and place the turkey breast in the center.
Brush half of the maple glaze over the turkey breast and return the pan to the oven for another 15 to 20 minutes.
Remove the pan, brush the remaining glaze over the turkey, and scatter the pecans over the sweet potatoes.
Roast for a final 5 minutes until the turkey reaches an internal temperature of 165°F and the pecans are fragrant.
Slice the turkey and arrange it on a platter surrounded by the roasted sweet potatoes and toasted pecans.