Make the pancakes and set aside until the filling is made.
Make the filling: Bring the cream to a simmer, and add sugar, rum, walnuts, raisins and orange rind. Simmer over very low heat for 1 minute. Adjust texture by adding alittle more cream or ground walnuts.
Put a heaping teaspoon of the filling in the center of each pancake. Fold in four instead of rolling.
Sauté the folded pancakes in butter in a large shallow pan for a few minutes on each side. Arrange the pancakes overlapping in a warm serving dish.
Make the sauce: Melt the chocolate in the milk over low heat. Whip in egg yolks and remove from heat. Mix in sugar, cocoa, butter and rum, and stir till smooth. Adjust thickness by adding alittle more milk if sauce is too thick to pour.
Pour sauce over the arranged pancakes, and serve at once, 2 pancakes for each serving.