In a medium size saucepan, cover the sweet potatoes with water and bring to a boil. Salt the water and cook the potatoes until just tender, 15-17 minutes. Drain and return the potatoes to the pot. Add the stock, cumin, cinnamon, thyme, zest and honey and mash. Season, to taste, with salt, pepper and the harissa.
Meanwhile, in a large, high-sided skillet, simmer the sausages in water to cook through, 8-10 minutes. In another skillet, crisp the sausages in a drizzle of EVOO over medium-high heat. Remove the sausages from the skillet and let stand for 5 minutes. Slice the sausages on an angle.
Spoon the mashed sweet potatoes into a shallow bowl and top with the sliced sausages. Garnish with the parsley and mint.