Stir together the 2 cups of cream and 1/4 cup of sugar, and refrigerate for at least 15 minutes.
Pulse chocolate in a food processor until finely grated.
Heat the 1/2 cup cream, 2 tablespoons of sugar, and water in a small saucepan until the sugar disolves. Raise heat and bring to a boil.
With food processor running, pour hot mixture through feed tube and process until the chocolate melts. Scrape bowl down, and add the vegetable oil. Pulse a few times to incorporate the oil.
Whip chilled cream on high till cream mounds into peaks. Fold whipped cream into the chocolate until no white streaks remain. Pour into cups or bowl, and refrigerate until set.
*** Can be kept in the refrigerator for 4 days or frozen and kept for 3 months.