Preheat oven to 425°. Spray standard 12-cup muffin tin with cooking spray. Heat large covered saucepot of water to a boil over high heat. Add pasta and cook as label directs; reserve 1/2 cup cooking water, then drain pasta.
In medium saucepan, melt butter over medium-low heat. In small bowl, whisk milk, cornstarch, dry mustard, reserved cooking water, and 1/4 teaspoon each salt and pepper; add to saucepan. Cook 5 minutes or until sauce thickens, whisking constantly; remove from heat. Stir in cheese and yogurt; fold in kale, nutritional yeast and pasta. Makes about 6 cups.
Divide pasta into prepared muffin tin cups; sprinkle with cracker snacks. Bake 20 minutes or until golden brown. Makes 12 cups.