You can shape these maple shortbread in two different ways: roll dough into a log shape and then slice rounds or roll between 2 sheets of waxed paper and then cut out with a maple cookie cutter.
Preheat oven to 300 degrees F. Line a baking sheet with parchment.
In a bowl, beat the butter until fluffy. Beat in the sugar until light and fluffy. Sift together the salt, rice and all-purpose flour. Add flour mixture to butter mixture and mix just until incorporated. Add vanilla and maple syrup and combine until just incorporated. Divide dough in half and roll into two logs, 1 ½-inches thick. Wrap in plastic wrap. Chill in refrigerator until firm, about 1 to 2 hours.
Once dough is chilled, cut into ¼-thick slices. Place on prepared baking sheets, spacing the cookies two-inches apart. Sprinkle each cookie with some granulated maple sugar.
Bake in the centre of the oven until edges are lightly golden, about 25 to 30 minutes. Cool on baking sheet on a wire rack, about 10 minutes. Transfer to wire racks to cool completely. Store in an airtight container. Makes about 20 cookies.