Sit the squash halves, cut-side up, in a large roasting tin, brush each with 1 tablespoon oil and season with salt and pepper. Roast in a preheated oven, 220°C (425°F), Gas Mark 7, for 45 minutes until lightly charred on top.
Meanwhile, heat the oil for the filling in a large, heavy-based frying pan, add the onion, garlic and cumin and cook over a medium-high heat, stirring occasionally, for 4–5 minutes until beginning to soften. Add the tomatoes, parsley, oregano and sun-dried tomato paste and cook, stirring occasionally, for a further 5 minutes. Season well with salt and pepper.
Divide the filling between the cavities of the roasted squash halves and scatter with the cumin seeds. Reduce the oven temperature to 180°C (350°F), Gas Mark 4, and roast the stuffed squash for 20 minutes, or until the filling is soft and golden in places. Serve with a simple rocket salad if liked.