In a medium-sized mixing bowl, mix butter, brown sugar, and vanilla extract until fluffy.
Mix in flour, salt, and instant coffee.
Stir in finely chopped hazelnuts.
Shape dough into eggs. I suggest having an egg on hand as a model. You could also use an egg serving tray like the one in the photo to test the eggs for size; your Easter egg cookies will not rise as they bake.
Freeze the cookie dough eggs for 20 minutes to help them hold their shape.
Bake on an ungreased cookie sheet covered with parchment paper or a silicone mat for 12 minutes.
Once cool to the touch, roll in powdered sugar. If you lift them off of the cookie sheet while they are still warm, they may crumble in your hands.
Wrap in colored foil.
You'll need colored foil candy wrappers in whatever colors you like (you can buy them at kitchen specialty shops or online).