Preheat the oven to 350°F. Stir together the dry ingredients in a large mixing bowl. In a separate bowl, mix the butter, eggs, coconut milk, evaporated milk, and vanilla extract, then incorporate the wet ingredients into the dry, vigorously stirring the mixture until homogeneous. (Because the rice flour doesn't contain batter-toughening gluten, don't hesitate to give the batter a few extra stirs to make sure the ingredients are well-combined.)
Pour the batter into a parchment-lined 8x8-inch square baking pan and set aside. In a small bowl, stir the 2 Tbsp. hot water into the strawberry jam, microwaving the bowl for 10 seconds at a time until the strawberry jam is warm and any chunks have loosened up into a runnier jam. Using a small spoon, drop dollops of jam on top of the mochi batter, trying your best to evenly distribute the jam over the batter. Bake mochi for 1 hour, until the top of the cake is golden and just browned around the edges.
Remove pan from oven and let cool for at least 20 minutes. Grasping the edges of parchment, carefully lift the baked mochi out of the pan. Flip the mochi upside-down onto a cutting board and peel off the parchment. The jam will have sunk to the bottom (now the top) of the cake. Let cool fully, and slice with a sharp knife into small pieces for serving.