Stir the cream and 1/3 cup of the sugar together in a large bowl. Beat the sweetened cream until soft peaks form. Set aside.

In a large bowl, using an electric mixer, beat the egg whites to soft peaks. Continue beating, adding the remaining 1/3 cup sugar 1 tablespoon at a time, until the whites form stiff, glossy peaks. Fold the cream mixture and beaten egg whites into the yogurt. Fold in the vanilla.

Line 1 large or 6 individual coeur a la creme molds or a large sieve with a double thickness of damp cheesecloth, allowing the excess to hang over the edge.

Fill the prepared mold(s) with the cream mixture and set over a large plate to drain. If using a sieve, set the sieve over a bowl. Fold the excess cheesecloth over the cream. Cover with plastic wrap and refrigerate for 24 hours.

Unwrap and invert the mold(s) onto a serving plate or plates. Remove the cheesecloth. Or, if using the sieve, invert onto a large plate and use an ice cream scoop to spoon individual servings into dessert bowls. Surround the coeur a la creme(s) with raspberry coulis and a few fresh raspberries

Variation: In a medium bowl, using a wooden spoon, beat 8 ounces softened mascarpone cheese, 1/2 cup sugar, and 1 teaspoon pure vanilla extract together until smooth and creamy. In a large bowl, beat 1 cup heavy cream until it forms soft peaks. Fold the whipped cream into the mascarpone cheese mixture. Mold, drain, and serve as in the above recipe.