In the bowl of a stand mixer fitted with the paddle attachment, beat 2 cups (250 grams) flour, ¼ cup (50 grams) sugar, yeast, and 1½ teaspoons (4.5 grams) salt at low speed until combined.
In a small saucepan, heat ½ cup (120 grams) milk, ½ cup (120 grams) water, 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, and beat at low speed until combined. Beat in 1 egg (50 grams) until combined. Add remaining 2 cups (250 grams) flour, and beat until a shaggy dough forms.
Switch to the dough hook attachment. Beat at low speed until dough is smooth and elastic, 8 to 10 minutes. (Dough should pass the windowpane test.) Turn out dough onto a clean surface, and shape into a smooth round.
Spray a large bowl with cooking spray. Place dough in bowl, turning to grease top. Cover and let rise in a warm, draft-free place (75°F/24°C) until doubled in size, 45 minutes to 1 hour.
In a medium bowl, combine hazelnuts, almonds, cocoa, cinnamon, remaining ¼ cup (50 grams) sugar, and remaining ¼ teaspoon salt. Stir in remaining ¼ cup (60 grams) milk and remaining 1 egg (50 grams).
Punch down dough, and let stand for 10 minutes. Roll dough into a 15×12-inch rectangle. Spread hazelnut mixture over dough, leaving a ¼-inch border on one long side. Starting with long side opposite border, roll up dough, jelly roll style. Cut in half lengthwise; place halves cut side up, and twist together. Pinch ends together, and tuck under. Place on a parchment paper-lined baking sheet. Cover and let rise in a warm, draft-free place (75°F/24°C) for 30 minutes.
Preheat oven to 375°F (190°C).
Bake until golden brown and an instant-read thermometer inserted in center registers 190°F (88°C) to 200°F (93°C), 25 to 30 minutes, covering with foil after 15 minutes of baking to prevent excess browning. Let cool completely on pan. Drizzle cooled loaf with Simple Glaze before serving.