Peanut Better Blossoms

Position oven racks in upper and lower thirds of oven. Preheat oven to 350°. Line two baking sheets with parchment paper.

In a medium bowl, whisk together flour, baking soda and salt; set aside. In a large bowl, beat 1/2 cup butter, the sugars and vanilla with an electric mixer on medium-low speed just until smooth and creamy, about 2 minutes. Add peanut butter; beat until smooth. Beat in egg until combined. Gradually add flour mixture, beating on low until dough comes together.

Drop level tablespoons of dough 11/2 inches apart on prepared baking sheets. Using a small measuring spoon with a deep well or a melon baller, make a 1-inch diameter indentation in centers of cookies.

Bake just until firm and golden brown on edges but still very soft in centers, about 12 minutes, rotating sheets from top to bottom and front to back about halfway through. Using whatever tool you used before, immediately re-indent cookies. Let cool on baking sheets 5 minutes; transfer to a wire rack to cool completely.

Place chocolate and 1/4 cup butter in a microwave-safe bowl. Microwave on high power in 30-second intervals, stirring until smooth. Let cool slightly. Transfer chocolate mixture to a small resealable plastic bag; snip off a tiny corner of bag. Squeeze chocolate mixture into indentations in cookies. (Alternately, use a small spoon to spoon chocolate mixture into cookies.) Let cookies stand about 1 hour at room temperature or refrigerate about 30 minutes or until set. Store in an airtight container at room temperature up to 1 week.