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  1. Preheat the oven to 350°F. Lightly grease a 9" square pan.

  2. Place the white chocolate and butter in a heatproof bowl. Heat at low power in the microwave at 1-minute intervals, or over simmering water, until the chocolate softens; white chocolate is sensitive to scorching, so be careful.

  3. When the butter is melted and the white chocolate looks soft, stir both together until smooth. Stir in the sugar, vanilla, nutmeg, and salt. Let the mixture cool to lukewarm (if necessary; it might already be fairly cool).

  4. Beat in the eggs.

  5. Whisk together the flour and baking powder, and stir into the egg mixture.

  6. Stir in 3/4 cup of the chocolate chunks. Spoon the batter into a greased 9" square pan, and sprinkle the remaining chocolate chunks over the top.

  7. Bake the brownies for 25 minutes, until they're light golden brown and the edges pull just slightly away from the pan.

  8. Remove from the oven, and cool before cutting.