radicchio, apple and pear salad

INGREDIENTS

• 1 extra-large egg yolk (I used one large and a smidgen of another)
• 1/2 cup plus 2 tablespoons grapeseed oil (suggested for its neutrality; I used half olive oil but suggest you do so sparingly as the olive flavor becomes very pronounced)
• 2 tablespoons finely diced shallot
• 1 to 2 lemons, for juicing
• 1/4 cup crème fraîche (did you know you can
• ?)
• 1/4 cup buttermilk (did you know you can
• 2 apples, firm, crisp and juicy
• 2 pears, Asian or your favorite variety
• 2 heads radicchio
• 2 tablespoons sliced mint
• 1 tablespoon chopped flat-leaf parsley
• Kosher salt and freshly ground black pepper