Baak Tong Gou, in Cantonese, or Bai Tong Gao, in Mandarin, is a beloved dessert that is popular at Chinese bakeries or dim sum restaurants. This steamed and lightly sweetened rice cake with a honeycomb-like interior is naturally nut-free, as well as free of the top 9 allergens. This recipe is adapted from Woks of Life's White Sugar Cake recipe (https://thewoksoflife.com/bai-tang-gao-white-sugar-sponge-cake/).
In a medium bowl, combine 3/4 cup water and the rice flour until the rice batter is smooth, set aside.
In a small saucepan, combine remaining ~1/3 cup water and remaining 1/4 cup sugar and cook on medium heat until the sugar melts, the water does not need to boil (3-4 minutes). Add the simple syrup to the rice batter and stir to combine. Check that the batter is just warm but not hot (due to boiling the syrup) and add the yeast and stir to combine. Cover the bowl of rice batter with plastic wrap.
Add more water to the cup of water from step 1 and microwave for 1 minute. Place the rice batter into the microwave next to the cup of hot water, close the door, and allow the rice batter to ferment for 3 hours.
About 10 minutes before the rice batter is done fermenting, set up a steamer in a large frying pan with a lid that can hold a pie plate or cake pan. Fill with about 1 inch of water and add a steamer rack, bring to boil.
When the cake is ready, turn the stove off, wait a minute or two, and carefully lift the lid. Brush with oil (optional step to keep the cakes moist). Cut the rice cake into approximately 8 pieces and they can be served warm or at room temperature.