Caramelizing Onions with Salt

Caramelizing Onions with Salt: Moisture Extraction for Faster Browning  

Adding 1/4 teaspoon salt to thinly sliced onions at the start of cooking is a technique that speeds caramelization by drawing out moisture. Salt causes onion cells to release their water content through osmosis, which then evaporates quickly in the hot pan. This means onions spend less time steaming in their own juices and more time browning, achieving deep golden caramelization faster. 

Thinly slicing onions also maximizes surface area for browning and ensures they soften completely without any crunchy bits in the sausage roll filling. The key is cooking them low and slow in olive oil until truly caramelized - deep golden brown with concentrated sweet flavor - not just softened and translucent. 

Properly caramelized onions add sweet complexity that balances the savory sausage meat and cuts through the richness of puff pastry. Don't rush this step; true caramelization takes 15-20 minutes and transforms raw onion's sharp bite into mellow sweetness.