Defrost the berries for about 20 minutes, letting them drip off. Divide into six ramekins (each containing approx. 330 ml) or a large form (approx. 2 l). Preheat the oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer).
For the zabaglione, wash the lemon hot, dab dry and finely grate the zest. Mix with egg yolk, white sugar and white wine in a metal bowl with a whisk or mixer. Then whip in a hot water bath for 7-10 minutes to a thick-foamed cream.
Remove from water bath, embezzle limoncello.
Pour zabaglione over the fruit. Sprinkle with brown sugar. Bake in a hot oven for about 10 minutes until a golden crust is formed. Serve immediately.