Preheat oven to 375ºF/190ºC: Warm, fragrant air is the first sensory cue, and you will notice the oven humming as it comes to temperature. A properly preheated oven ensures even heat penetration so the berries roast rather than steam. The slight warmth around the oven door and the steady heating sound tell you it is ready. Common mistakes include skipping preheating, which can result in uneven cooking, or setting an incorrect temperature, which either chars the edges too fast or prevents caramelization.
Hull the strawberries and cut them all in half: The texture becomes tactile and slightly sticky as you work, with the green caps coming away cleanly. Cutting the berries exposes their juices so they can caramelize on the cut surface, creating concentrated pockets of flavor. I use a small, sharp knife and steady pressure to keep halves uniform; uneven pieces will roast at different rates. Avoid tearing the fruit, because ragged edges can overcook and dry out.
Line a large sheet pan with parchment paper, folding over the edges so any juices don't escape.: As you press the parchment into place there is a papery, dry sound, and the pan looks ready to contain bubbling juices. Parchment prevents sticking and makes cleanup effortless, while folded edges catch runaway syrup. If you skip this protection, juices can burn onto the pan and cause unpleasant smoke later. A common oversight is using too small a pan, which crowds the berries and leads to steaming rather than roasting.
Toss strawberries with the sugar, oil and salt until thoroughly coated.: You'll feel the coatings slicking the fruit, and the sugar will start to melt slightly as it warms against your hands. This even coating is important for consistent browning and flavor distribution. I toss gently so the berries keep their shape while every surface gets a touch of seasoning. Overmixing can bruise them, creating mushy patches that release too much juice.
Arrange the strawberries to the sheet pan cut side down.: Laying each half cut side down creates a glossy sear where juices concentrate and caramelize, and visually you can see neat rows of red domes. This orientation protects the delicate flesh and encourages even browning, giving the final fruit a pleasing texture. If you place them cut side up, juices spread across the pan and caramelization will be uneven. Crowding is another pitfall here, because touching berries will steam each other instead of roasting.
Roast for 20 minutes, or until they start to caramelize.: During roasting the kitchen fills with a warm, sugary aroma and you may hear a faint bubbling as juices reduce. Look for edges to darken and for the surfaces to glisten with syrup, that is your cue they are approaching readiness. This stage concentrates flavors and alters texture to a tender yet slightly structured bite. Avoid walking away completely; if you leave them too long they can go beyond caramelization to char, which introduces bitterness.
Remove from oven and allow to cool slightly before using them in your chosen way.: As the tray cools you will notice the syrup thicken and the aroma mellow into a rich, deep berry perfume. Cooling allows juices to set a little so the berries hold shape when stirred into other dishes. I often let them rest ten to fifteen minutes to make handling easier and to avoid burning when tasting. A common error is trying to use them piping hot, which can cause them to break down into a thin sauce rather than a spoonable compote.