Sloe Sazerac

In a cocktail shaker or mixing glass filled with ice, combine everything except the absinthe and lemon peel and berries, if using. Stir well until diluted to taste. Pour the absinthe into an old fashioned glass and swirl to coat the interior. Discard the excess. Strain the mixture from the shaker into the glass and garnish with lemon peel and berries, if you like.