Spray two 8-ounce coffee mugs (or small ramekins) lightly with cooking spray.
Tear donuts into 1-inch pieces.
In a small bowl, whisk together the eggs, milk, sugar, and vanilla. (Add any other stir-ins you prefer.)
Add the donuts to the bowl with the eggs and milk and stir well.
Divide the mixture between two mugs.
Place the mugs on a small baking sheet, and bake for 30-35 minutes. The mixture will puff up and rise slightly.
Serve with a caramel or chocolate and whipped cream or ice cream.
Be careful the mugs will be really hot.
For the sauce
In a small saucepan over medium heat, stir together all the sauce ingredients.
Bring to a simmer, stirring frequently. Remove from the heat. The sugar should be dissolved.
After the bread pudding mugs are removed from the oven, the sauce will absorb better if you'll take a knife and run it around the edges then pour the hot sauce over the bread pudding.
For any leftover sauce, store in an airtight container in the refrigerator for a few days.
optional: 2 tablespoon blueberries, chopped dates, raisins, or other fruit, nuts, or chocolate chips
optional: serve with a drizzle of caramel or chocolate sauce and whipped cream or ice cream