Curried Cauliflower and Potato Salad

Name: Curried Cauliflower and Potato Salad
Ingredients: 3 cups roasted cauliflower florets; 3 cups roasted Red Bliss potatoes; 1 teaspoon coriander seeds; 1 teaspoon cumin seeds; 1 teaspoon fennel seeds; 1 tablespoon curry powder; 1/4 teaspoon cayenne pepper; 3/4 cup diced roasted red bell peppers; 1/4 cup chopped cilantro; 1/2 cup mayonnaise; 1/4 cup plain yogurt; 1/2 small red onion, julienned; 1/2 cup thinly sliced celery; Juice and zest of 1 lemon; Kosher salt and freshly ground black pepper; 1/4 cup finely sliced green onions (white and light green parts), for garnish