• Preheat oven to 325°F (170°C). Line a baking sheet with parchment paper.
• In the bowl of a stand mixer fitted with the paddle attachment, beat butter and sugars at medium speed until fluffy, about 3 minutes, stopping to scrape sides of bowl. Beat in eggs, vanilla bean paste, and almond extract. (Mixture may look a bit broken, but dough will come together.)
• In a medium bowl, whisk together flour, baking powder, and salt. With mixer on low speed, gradually add flour mixture to butter mixture, beating until combined.
• Divide dough in half. Shape half of dough into a rough 6½x5-inch rectangle. (Keep remaining dough covered to prevent it from drying out.) Place dough rectangle on a lightly floured sheet of parchment paper, and lightly flour top of dough; place another sheet of parchment on top of dough. Roll dough between parchment into a 12x8-inch rectangle; lightly flour dough on both sides to prevent sticking as needed. Remove top parchment. Using a small off set spatula, spread half of hazelnut chocolate spread on top of dough, leaving a ½-inch border around edges. Sprinkle with half of very finely chopped hazelnuts. Starting on one short side and using parchment to help support, roll up dough, jelly roll style. Pinch ends to seal, and tuck edges under to create a rectangular block (about 1 inch tall). Place dough, seam side down, on prepared pan. Repeat procedure with remaining dough, remaining hazelnut chocolate spread, and remaining very finely chopped hazelnuts. Space dough rectangles 3 to 4 inches apart on prepared pan.
• Bake until golden brown and edges are set, 35 to 40 minutes. (Dough will crack along the top a little—this is normal). Let cool on pan for 10 minutes. Leave oven on.
• Carefully transfer dough to a cutting board. Using a serrated knife, carefully cut dough diagonally into ¾-inch-thick slices. Place slices, cut side down, 1 inch apart on parchment paper-lined baking sheets.
• Bake until toasted and centers are mostly dry and firm, 30 to 37 minutes (see Note), turning biscotti halfway through baking. Remove from pan, and let cool completely on a wire rack.
• Drizzle or spread Hazelnut Chocolate Glaze onto cooled biscotti. Garnish with chopped hazelnuts, if desired. Serve immediately, or let stand until glaze is set, about 30 minutes.

Hazelnut Chocolate Glaze

• In a small bowl, stir together confectioners’ sugar, hazelnut chocolate spread, 2 tablespoons (30 grams) water, and salt until smooth and well combined. Use immediately.