Step 1Place the piloncillo into a wide, heavy pot, and pour over the water. Add the cinnamon and cloves, and bring the mixture to a simmer over medium heat, stirring occasionally until the piloncillo has fully dissolved, making a loose syrup. It will take 10 to 15 minutes.
Step 2While the piloncillo is dissolving, rinse the pumpkin clean. Cut the pumpkin into wedges or large chunks roughly 3 inches square. Some cooks remove the strings and seeds, some don't.
Step 3Once the piloncillo is dissolved into the water, remove the pot from the heat and begin adding the pumpkin pieces. Arrange the pieces leaving space in between so the syrup can be absorbed.
Step 4Cover the pot and place it over medium to medium-low heat until the pumpkin begins to soften, about 1 hour. Uncover and continue cooking until the liquid is reduced to a thick syrup and the pumpkin is richly colored and soaked with syrup, about 30 minutes more. Remove from heat and set aside until the pumpkin is cooled. The pumpkin will keep, refrigerated, up to 1 month.