These are my son's fave -- one of them, anyway.

1/2 cup smooth peanut butter
1/4 cup unsalted butter, at room
temperature
1/2 cup sugar
1/4 cup packed brown sugar
1 large egg, at room temperature
3/4 cup flour
1 teaspoon baking soda
5 ounces coarsely chopped white
chocolate, divided

1. Position a rack in the center and preheat oven to 400 degrees F.
Lightly butter two baking sheets. Using an electric mixer set at
medium speed, cream the butters and sugars in a large bowl until
smooth. Beat in the egg until incorporated.
2. In a small bowl, combine the flour and the baking soda. Beat the
flour mixture into the butter mixture. Cover and refrigerate the
dough for 10 minutes.
3. In a double boiler over hot-not-simmering-water, melt half of
the white chocolate, stirring frequently. Cool to room temperature.
4. Remove the dough from the refrigerator and divide it into two
equal parts. Place half of the dough into a medium bowl. Using an
electric mixer set at medium speed, blend the melted white chocolate
into the dough.
5. Place the remaining dough in a medium bowl. Using a electric
mixer set at medium speed, blend the chopped white chocolate into the
dough.
6. Roll the dough into 1-inch balls. Place the dough balls on the
prepared baking sheets about 1 inch apart. The cookies will puff and
spread slightly. Bake until light golden in color, about 6 to 8
minutes. Transfer the cookies to a wire rack and cool completely.
Store in an airtight container.

Do ahead: The peanut butter cookies can be made up to 2 days in
advance.

Makes about 34 cookies.