Make the dough: In the bowl of a stand mixer, whisk together 4½ cups (563g) flour, cocoa, sugar, yeast, coffee granules, and salt.
In a small saucepan or microwave-safe dish, heat milk and butter over medium heat until butter is melted and an instant-read thermometer registers 120°F (49°C) to 130°F (54°C). Add warm milk mixture to flour mixture; using the paddle attachment, beat at low speed until combined, about 2 minutes. Add egg, and beat until a shaggy dough forms; scrape sides of bowl.
Switch to the dough hook attachment. Beat at medium-low speed until dough becomes smooth and elastic and begins to pull away from sides of bowl, 9 to 11 minutes; add up to remaining ¼ cup (31g) flour, 1 tablespoon (8g) at a time, if the dough is too sticky. Turn out dough, and shape into a round. Cover and let stand for 15 minutes.
Make the filling: In a small bowl, mix together brown sugar, ground almonds, cinnamon, butter, and cocoa.
Spray a 13x9-inch baking dish with baking spray with flour.
Turn out dough onto a lightly floured surface. Roll into a 25x12-inch (about 1/5-inch thick), with one long side facing you. Using a knife or spatula, carefully spread butter mixture onto dough, leaving a 1-inch border along one long side. Sprinkle sliced almonds evenly over surface. Starting with long side opposite border, tightly roll up dough into a log, pinching seam to seal. Using a serrated knife, cut ½ inch off either side. Cut remaining dough into 12 slices (about 2 inches each), and place in prepared pan. Cover and let rise in a warm, draft-free place (75°F/24°C) until puffed, 45 to 50 minutes.
Preheat oven to 350°F (180°C).
Bake until centers are just set and an instant-read thermometer inserted in center registers 190°F (88°C), 30 to 35 minutes.
Make the Glaze: (makes 1/2 cup) In a medium microwave-safe bowl, combine white chocolate, milk, and butter. Heat on high in 30-second intervals, stirring between each, until white chocolate is melted. Stir until combined. Add confectioners’ sugar and vanilla. Whisk until smooth.
Let rolls cool in pan for 10 minutes. Drizzle White Chocolate Glaze over the tops of the rolls; garnish with sliced almonds, if desired. Best served warm.