Hazelnut

Weighed in grams; no household-spoon or count conversion given.

Instead of Hazelnut

Nothing truly matches hazelnut's sweet earthy skin-on flavour; almond is the closest everyday nut.

Almond
Use the same weight. Toast first and blanch if the recipe wants skinless nuts; the flavour is milder and less earthy.
Cashew nut
Use the same weight. Cashews are softer and sweeter, so reduce any added sugar slightly; they grind smoother.
Walnut
Use 80–90% of the weight. Walnuts are stronger and slightly bitter, so toast lightly; good in chutneys but not delicate sweets.