In a small bowl, dissolve the sugar in 1/2 cup of warm water. Sprinkle the yeast over the water and let it sit for about 5-10 minutes until frothy.
In a blender, combine the rice flour, cooked rice, salt, coconut milk, and the yeast mixture. Blend until smooth. The batter should be thin, similar to crepe batter. Add more water if needed to achieve the right consistency.
Transfer the batter to a large mixing bowl, cover with a clean cloth, and let it ferment in a warm place for about 6-8 hours or overnight.
After fermentation, stir the batter well. If it has thickened too much, add a little more water to reach the desired consistency.
Heat a small, non-stick or well-seasoned hopper pan (or small wok) over medium heat. Lightly grease the pan with vegetable oil or coconut oil.
Pour a ladleful of batter into the pan, swirling the pan to spread the batter thinly around the sides, leaving a small pool of batter in the center.
Cover the pan with a lid and cook for about 2-3 minutes until the edges are golden brown and crisp, and the center is cooked through.
For egg hoppers, crack an egg into the center of the hopper after swirling the batter around the sides. Cover and cook until the egg is set to your liking.
Repeat with the remaining batter, greasing the pan as needed.
Enjoy your meal!