1) In a saucepan, heat the cream to simmering over high heat. Reduce the heat to medium and whisk in the chocolate until melted. Gently simmer the sauce for 10 minutes. Set aside.
2) Make a light sugar syrup by heating the water and sugar together in a medium-sized saute pan, stirring until the sugar is dissolved.
3) Add the lemon juice and berries to the syrup and cook over medium heat for 2 to 3 minutes, shaking the pan to gently to coat the berries with the syrup. Add the butter and continue to cook, swirling the berries and butter around the pan until the butter is melted. Cook for another 5 minutes.
Spoon the berry compote into four ramekins, drizzle with the white chocolate sauce and serve.