Leftover Blue Cheese Chicken Salad Sandwich

2 ounces Gorgonzola dolce, crumbled

1/4 cup plain Greek yogurt

1 1/2 tablespoons extra-virgin olive oil

1 tablespoon Champagne vinegar

1/2 tablespoon minced shallot

1/2 teaspoon fresh lemon juice

Kosher salt

Freshly ground black pepper

2 cups rotisserie chicken, diced

1/2 cup celery, thinly sliced

1 baguette, split lengthwise

1/2 cup sugar snap peas, thinly sliced

1/2 cup radishes, thinly sliced

1/2 cup torn lettuce or mesclun