Rinse the glutinous rice to remove any dirt or debris. Place it in a bowl and add water until it's about an inch above the rice level.
Add 1½ teaspoons of lye water and mix well for even distribution. Cover and refrigerate overnight to soak the rice for about 8 hours.
After soaking, drain off any remaining water and rinse under tap water to remove excess lye water. Bring it back to the bowl and add ½ teaspoon of kosher salt (use half for table salt). Mix it well.
Prepare 20-22 banana leaves, about 8 x 10 inches for the outer wrap, and an equal number of smaller leaves for the inner wrap. Rinse or wipe them clean, then heat quickly over an open flame or in a microwave to increase flexibility. Remove the central rib for easier wrapping.
Lay a smaller inner leaf on top of a larger outer leaf, both horizontally. Place ¼ cup of rice in the center of the inner leaf and wrap it snugly, allowing room for expansion. Fold the larger leaf over this, covering it completely and folding in the sides to form a compact rectangle. Place two wrapped suman side by side with the folds facing each other and tie them together with kitchen twine or a strip of banana leaf.
Arrange the suman in a pot, then pour enough water to completely submerge them. Bring it to a boil, then reduce the heat to keep the water bubbling steadily but not too vigorously, for about 2 hours. The rice should be tender, sticky, and fully cooked through.PRO TIP: Keep the packages submerged throughout the cooking process; weigh them down with a heat-proof plate or pot lid if needed. If the water level drops, replenish it with more boiling water to keep the suman fully covered. In a saucepan, combine coconut, panutsa, a pinch of salt, and vanilla extract. Crack or break the panutsa into smaller pieces to melt more easily and evenly into the coconut milk.
Set over medium-high heat, stirring occasionally to melt the panutsa and prevent sticking or burning. Continue cooking until it reduces in volume and thickens, about 15 minutes.To check if the sauce is thick enough, dip a spoon into it. If it coats the spoon and drips slowly, it's ready. Alternatively, drop a bit on a plate and let it cool; if it thickens to your desired consistency, the sauce is ready. This recipe yields about 1¾ cups of latik sauce. Once the Suman sa Lihiya has cooled slightly, unwrap and serve them with a generous drizzle of latik sauce.