Irish Coffee Sundaes with Caramel Whiskey Sauce

INGREDIENTS

• 1/4 teaspoon salt
• 6 Tablespoons Irish whiskey
• 1/4 cup packed light brown sugar
• 1 cup walnut pieces (3 1/2 ounces), coarsely chopped if desired
• 1 cup granulated sugar
• 1/4 cup water
• 1/4 cup heavy cream
• 1/2 teaspoon instant coffee granules, crushed
• 1 large egg white
• 2 pints good-quality coffee ice cream