3 parts rye
2 parts aperol
2 parts dry vermouth
orange bitters
1 orange twist

Shake with ice, serve up in a coupe with the twist.

Via http://www.bonappetit.com/recipe/old-pal, modified to use rye and add bitters to counteract the sweetness of switching this to aperol (which I stock) from campari.

Recipe for aging

This, called instead a Lincoln County, is via http://www.bonappetit.com/recipe/lincoln-county ; original recipe by The Bachelor Farmer Marvel Bar in Minneapolis MN
4 1/4 cups 100-proof bourbon
2 1/2 cups Campari
1 2/3 cups Carpano Antica Formula Vermouth
1 lb. 100% natural hardwood lump charcoal (no chemicals or accelerants; broken into 1" pieces with a cleaver or large knife)

Mix ingredients in a large jar. Cover and let stand in a cool, dark place for 10 days.

Strain through a coffee filter into another large jar or pitcher; repeat until mixture is sediment-free (use a clean filter each time you strain, about 3 times). Return to jar. Cover.

Fill a large glass with ice cubes and add 1/4 cup strained cocktail mixture. Stir until outside of glass is very cold. Strain into a coupe or Martini glass.

Further variations

The Straight Up blog proposes the New Friend: http://drinkstraightup.com/2014/04/02/new-friend/

Add equal parts rye whiskey, Aperol and Cocchi Americano to a chilled mixing glass. Add ice and stir until well chilled. Strain into a chilled cocktail glass and garnish with an orange twist.