French Onion and Blue Cheese Dip

INGREDIENTS

• 2 Tbs. unsalted butter
• 1 large yellow onion, finely diced
• 1 tsp. kosher salt
• 1 garlic clove, minced
• 2 tsp. Worcestershire sauce
• 1 1/4 cups sour cream
• 1/4 cup mayonnaise
• 1/8 tsp. cayenne pepper
• 1/4 tsp. freshly ground black pepper
• 2 oz. blue cheese
• 2 Tbs. milk, plus more as needed
• Potato chips and crudités for serving