Preheat oven to 350°F (175°C). Roast 1 1/4 cups (150g) of hazelnuts for 10-12 minutes. Remove skins with a towel, cool, and pulse 1 cup (120g) in a food processor until finely ground. Reserve the rest for garnish.

Simmer 1/2 cup (120ml) water and 1/2 cup (100g) granulated sugar in a saucepan. Drop in 3 orange peel strips and simmer for 15 minutes. Remove, twist into spirals, and let harden on parchment paper.

Whisk together 1 1/2 cups (180g) all-purpose flour, 1 cup (120g) ground hazelnuts, 1 tbsp (15g) baking powder, and 1/2 tsp (3g) salt in a medium bowl.

Beat 1/2 cup (113g) softened butter, 1 cup (200g) granulated sugar, and 2 tbsp (12g) orange zest for 3 minutes until pale and fluffy. Beat in the 3 large eggs one at a time.

Fold the dry flour mixture into the butter mixture in three additions, alternating with the 3/4 cup (180ml) buttermilk. Mix just until no flour streaks remain.

Pour into a greased and parchment-lined 9-inch round pan. Bake at 350°F (175°C) for 40-45 minutes until a toothpick comes out clean. Cool for 15 minutes in the pan, then transfer to a wire rack to cool completely.

Whisk 1 cup (120g) sifted powdered sugar with 2 tbsp (30ml) fresh orange juice until smooth and translucent.

Pour the glaze over the cooled cake, letting it drip down the sides. Immediately top with the 3 twisted candied orange peels and sprinkle with reserved crushed roasted hazelnuts.