Preheat oven to 350 degrees F and grease an 8x8" baking dish.
Mix all ingredients in a large mixing bowl, stirring well to ensure no dry lumps of flour remain.
Pour into your prepared baking dish and bake for 45 minutes or until a toothpick inserted in the center comes out clean.
Allow butter mochi to cool before slicing and serving. Leftover butter mochi will keep in an airtight container at room temperature for a few days.
