Preheat your wood oven to medium, or a regular oven to 180°C/350ºF/gas 4. Trim, destone and slice the fruit into large chunks, then place into a roasting tray. Hull and add the strawberries, along with 50g of sugar, the orange zest and juice and the lemon verbena (if using). Place at the front of your oven and roast for 20 minutes, or until syrupy and softened.
Meanwhile, for your crumble topping, use your fingers to lightly rub the flour into the butter until the mixture resembles fine crumbs. Chop and stir in the ginger, then add the oats and the rest of the sugar (you can make the topping in a food processor – just whack in the flour, butter, sugar and ginger and whizz up. Add the oats for the last 10 seconds). Sprinkle the topping over the fruit and bake for 40 to 45 minutes, or until the fruit is bubbling up and the topping is golden.