Combine 3 chopped ripe plantains in a saucepan with 2 cinnamon sticks, 1/4 cup brown sugar, 4 tablespoons butter and 1 teaspon kosher salt. Cover with water and simmer until tender, 15 to 20 minutes. Drain, reserving the liquid. Mash the plantains. Brown 4 tablespoons butter in a skillet, 6 to 10 minutes. Mix into the plantains; add enough of the reserved liquid until creamy. Season with salt, pepper and ground cinnamon.