Preparation Combine first 6 ingredients in medium bowl. Using electric mixer, beat brown sugar and butter in large bowl until light. Add egg and beat until fluffy. Gradually add dry ingredients and beat just until combined. Divide dough in half. Flatten each half into rectangle. Wrap with plastic; chill 1 hour. Preheat oven to 350°F. Lightly butter 2 large baking sheets. Roll out 1 dough piece on lightly floured work surface to 13 x 9-inch rectangle. Trim edges to form 12x8-inch rectangle. Cut into 24 4x1-inch rectangles. Lightly press miniature cookie cutter into each rectangle to make imprints (do not cut through dough). Arrange cookies on prepared baking sheets, spacing 1 inch apart. Bake until edges begin to darken, about 8 minutes. Transfer cookies to rack and cool. Repeat with remaining dough piece. Working with 1 cookie at a time, brush imprints with melted white chocolate. Sprinkle colored sugar generously over chocolate. Let stand until chocolate sets, about 2 hours. Shake off excess colored sugar. (Can be made ahead. Store in airtight container at room temperature up to 1 week, or freeze up to 1 month.)
Preparation Combine first 6 ingredients in medium bowl. Using electric mixer, beat brown sugar and butter in large bowl until light. Add egg and beat until fluffy. Gradually add dry ingredients and beat just until combined. Divide dough in half. Flatten each half into rectangle. Wrap with plastic; chill 1 hour. Preheat oven to 350°F. Lightly butter 2 large baking sheets. Roll out 1 dough piece on lightly floured work surface to 13 x 9-inch rectangle. Trim edges to form 12x8-inch rectangle. Cut into 24 4x1-inch rectangles. Lightly press miniature cookie cutter into each rectangle to make imprints (do not cut through dough). Arrange cookies on prepared baking sheets, spacing 1 inch apart. Bake until edges begin to darken, about 8 minutes. Transfer cookies to rack and cool. Repeat with remaining dough piece. Working with 1 cookie at a time, brush imprints with melted white chocolate. Sprinkle colored sugar generously over chocolate. Let stand until chocolate sets, about 2 hours. Shake off excess colored sugar. (Can be made ahead. Store in airtight container at room temperature up to 1 week, or freeze up to 1 month.)