To make the compote, melt the butter in a medium-sized pot over medium heat. Add the brown sugar, apple juice, and cinnamon. Bring to a simmer and reduce heat. Let cook for about 5 minutes. Add the apples and continue to cook for 10 to 15 minutes, or until the apples are softer and the liquid is a little thicker.
For the french toast, whisk together the eggs, milk, and vanilla. Slice the hot cross buns in half. Heat a pan over medium heat and add bacon fat or canola oil for frying. Once hot, dip the hot cross buns in the whisked egg mixture then fry for a couple of minutes on each side, until golden brown.
To serve, top french toast with apple compote and butter, if desired.