Peel your sweet potatoes and cut into 2 inch pieces. To an 8 quart heavy bottomed pot, add the sweet potato chunks, brown sugar, granulated sugar, lemon zest, lemon juice, evaporated milk, heavy cream, cinnamon stick, ground cinnamon, ginger, cloves, nutmeg, salt and vanilla extract. Cook, covered over medium/low heat until the sweet potatoes are very tender, about 30 minutes.