To prepare a steamed green pear cake decorated with water caltrop cake recipe, first you need to prepare the cake batter. First, you'll need the following ingredients: 1 cup (240 ml) of water, 1 tbsp. of sugar, and 1 tablespoon of vegetable oil. Add the dry ingredients to the wet ingredients and mix well. Pour the batter into the pan and cook on medium-high heat until it starts to bubble and turn golden brown, about 5 minutes. Then, add the water and stir the mixture to make sure it doesn't stick to your pan. Cook for an additional 2 to 3 minutes, then remove from the heat.