CUT the angel food cake into 1-inch cubes. Aim for 4 cups, but you can make croutons out of any amount of cubes.
LAY the cake cubes on a baking sheet and allow them to dry out. Overnight is the minimum if you are using fresh cake. However, 24 to 48 hours is better. (See note #1)
PREHEAT the oven to 250°F (120°C).
PLACE the dried cake cubes in a large mixing bowl.
MELT the coconut oil or butter. Drizzle the melted fat over the dried cake cubes. Stir to distribute it over all the cake cubes.
SPRINKLE the sugar into the cake cubes. Shake and stir the cake cubes until all the pieces are coated.
Optional: SHAKE the cake cubes through a mesh strainer to remove excess sugar.
LINE a baking sheet with parchment paper (or spray with baking spray). Lay the cake cubes on the baking sheet in a single layer.
PLACE the baking sheet in the hot oven and toast for 10 minutes.
FLIP the cubes over and toast for another 10 minutes.
STIR and flip one last time and toast for another 10 minutes or until the croutons are crunchy. Keep an eye on the croutons during the last few minutes, so they don’t burn. If necessary, stir and bake for another 10 minutes.
REMOVE the pan from the oven and turn the oven off. Cool the cake croutons completely.
USE immediately or store in an airtight container for up to a week. For longer storage, freeze up to 6 months.