Preheat the oven to 400ºF (200ºC). Peel the sweet potatoes and cut into 1-inch (2.5-cm) cubes. Toss with 2 Tbsp. (30 mL) olive oil, cinnamon, cumin, cayenne, and salt. Roast for 25 to 30 minutes, turning once or twice until cooked through and golden brown.
While the potatoes are roasting, heat the vegetable oil in a shallow pot. Add the sliced shallots in batches and fry, stirring, until they are dark golden and crispy. Drain and reserve. Spoon the warm potatoes into a serving bowl. Core and cut the pears into 1/8-inch (3-mm) slices and add to the sweet potatoes.
In a small bowl, stir together the lemon and orange juice. Whisk in the olive oil and then the basil. Season with salt and pepper.
Gently toss the vinaigrette into the sweet potatoes and pears and sprinkle with the crispy shallots.
Serve while the sweet potatoes are still warm.
Photo by Doug Bradshaw.