Arrange a large bamboo steamer or standard rice cooker steamer over simmering water.
Line the steam basket with parchment paper.
Macerate strawberries and chopped orange with 1 tbsp of the Orange Vanilla Sugar.
Beat eggs, sugar and soy milk.
Blend flour and baking soda, then combine with four mixture.
Pour the batter into the prepared pan, and smooth out to edges.
Rap the pan on the counter to get rid of large air bubbles.
Arrange sliced oranges on top.
Place the pan into the steamer. Cover the top of the steamer with a kitchen towel, and place the lid on top; the towel will absorb any steam that collects on top from dripping onto the cake.
Steam for about 30 minutes or until a toothpick inserted into the center comes out clean.