In a medium saucepan, cover the sweet potatoes with water and bring to a boil. Salt the water and cook the potatoes until just tender, 15 to 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 harissa.
Meanwhile, in a large, high-sided skillet, simmer the sausages in water to cook through, 8 to 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 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.