The simple glaze adds a sweet hint of maple. Makes a delicious hostess gift, packed in pretty containers.
In large bowl, using electric mixer, beat butter with brown sugar until fluffy. Beat in maple syrup and vanilla. Beat in eggs, 1 at a time. In separate large bowl, whisk together flour, baking powder, baking soda and salt; stir into butter mixture in 2 additions to form slightly sticky dough. Stir in walnuts.
Divide dough in half. On lightly floured surface, roll each into a 12-inch (30 cm) long log. Place 3-inches (8 cm) apart on parchment paper-lined baking sheet. Press to flatten to 2 1/2-inches (6 cm) wide. Bake in 325°F (160°C) oven for about 30 minutes or until light golden and firm to the touch. Let cool on pan on wire rack for 15 minutes.
Transfer logs to cutting board; cut crosswise on slight diagonal into 1/2-inch (1 cm) thick slices. Stand slices up, 1-inch (2.5 cm) apart, on baking sheet. Bake in 300°F (150°C) oven for about 30 minutes or until almost dry. Transfer to wire rack; let cool completely.
Maple Glaze: In small bowl, whisk icing sugar with maple syrup. With cooled biscotti sitting side by side, drizzle glaze over tops. Separate slightly and let stand until set, about 15 minutes.