Step 1

Heat ¼ cup oil in a medium saucepan over medium heat. Add onion, carrot, celery, and chiles; season with salt and cook, stirring occasionally, until vegetables are very soft but not brown, 12–15 minutes. Let soffritto cool.

Step 2

Preheat oven to 450°. Heat 2 Tbsp. oil in a large skillet over medium-high heat. Add half of Romanesco and cook, undisturbed, until deeply browned, about 4 minutes. Transfer to a roasting pan; repeat with remaining 2 Tbsp. oil and remaining Romanesco. Add soffritto, anchovies, and wine to roasting pan; season with salt and pepper and toss to combine.

Step 3

Roast, tossing halfway through, until Romanesco is soft and liquid is mostly evaporated, 25–30 minutes; season with salt and pepper and top with mint.