Thoroughly butter a 10-inch springform pan.
In a large metal bowl set over a pan of barely simmering water melt chocolate, stirring occasionally, until smooth. Remove from heat and stir in butter, a few pieces at a time, until fully incorporated.
In a large bowl beat egg yolks with 1/4 cup of the sugar until thick and pale. In another bowl whisk egg whites with remaining 1/4 cup sugar to stiff peaks.
Into warm chocolate mixture fold egg yolks, then egg whites. Spread 1 cup of the pecans into cake pan and pour chocolate mixture over. Sprinkle remaining 1/2 cup pecans over top and refrigerate overnight.
To unmold, run a knife around edges of pan and carefully release springform. To serve, spoon 1 to 2 tablespoons white chocolate sauce onto each chilled plate and top with a slice of terrine. Top with a dollop of whipped cream and a few coffee beans.
Yield: 12 servings