Homemade Hazelnut Liqueur
from http://www.seriouseats.com/

Frangelico is the most well-known hazelnut liqueur, and it's easy to find at liquor stores for about $20 a bottle. Hiram Walker, Gaetano, and DeKuyper also make hazelnut liqueurs—they're closer to $10.

While hazelnut liqueur isn't that hard to find, it's still worth it to make your own because the flavor is better. Homemade hazelnut liqueur has a clean nutty flavor that's stronger and more natural-tasting than in its commercial counterparts. And the potential for experimentation in small batches makes it as entertaining as it is delicious.

This recipe goes light on the sugar, so add more simple syrup to taste if desired.

1/2 pound raw hazelnuts with skin, roughly chopped (about 2 cups)
1 cup vodka
1/2 cup brandy
1/4 cup sugar
1/4 cup water
1 vanilla bean, split

Combine chopped hazelnuts, vodka, and brandy in a sealable jar. Shake and let steep at room temperature for 2 weeks.

Combine sugar and water in a small saucepan and heat until sugar is dissolved. Let cool, then add to the hazelnut mixture. Shake and let steep for more 3 days, then add the vanilla bean and let steep for additional 3 to 5 days.

Sample often. Once desired flavor is achieved, strain through sieve and then again through cheesecloth or coffee filter. Refrigerate for up to 2 months.