The typical method to refresh a dried-out bagel is to heat it in an oven or toaster. This skips the crucial step of soaking the bagel in water before reheating it.
To restore your bagel’s soft and chewy texture, soak it in hot water or run it under the tap before baking it in an oven heated to 350 degrees Fahrenheit for around five minutes.
Once the moisture in the rehydrated bagel turns to steam, it’ll soften the inside and restore some outer crispness. For an even moister interior, wrap it in foil before baking.
You can either wrap the bagel in a damp paper towel and microwave for 15 seconds or sprinkle water on the plate beneath the bagel and microwave for 30 seconds.