In a chilled bowl, whip 1 cup of the heavy cream until it forms soft peaks.
Melt chocolate and add 1/2 cup of whipped cream and mix well.
Spread the chocolate mixture over the bottom and up the sides of the crust and refrigerate until set.
In a food processor, blend peanut butter, yogurt and sweetened condensed milk.
Add the remaining whipped cream and mix well.
Pour into the crust and refrigerate overnight (or until set, about 2 hours).
When ready to serve, whip the remaining heavy cream and top each slice with a dollop of whipped cream and sprinkle with chocolate shavings.