Heat oven to 350 degrees F. Lightly oil the top surface of a 12-cup muffin tin.
Line the cups with paper liners.
In a double boiler, melt the chopped semisweet chocolate with the butter and
stir until smooth. Remove from the heat and stir in the sour cream.
In a small bowl,
whisk together the flour, baking soda and salt. In a large bowl with an electric
mixer, beat the eggs and sugar until light and pale, about 5 minutes.
Beat in the chocolate mixture and the vanilla. Add the flour mixture and 1 cup
of the semisweet chocolate chips. Spoon the batter evenly into the prepared muffin
cups. Top with the remaining 1/4 cup semisweet chips, the macadamia nuts and the
white chocolate chips.
Bake at 350 degrees F for 20-25 minutes or until wooden
pick inserted in center comes out clean.
Put the muffin tin on a wire rack to cool for 15 minutes.