Sunnys Nutty Sweet Potato Souffle

Name: Sunny's Nutty Sweet Potato Souffle
Ingredients: 2 tablespoons unsalted butter; 1 cup pecan halves; 1/2 cup light brown sugar; 12 to 14 leaves fresh sage; 1/2 teaspoon ground cinnamon; Kosher salt; Two 1 1/2-pound steamable sweet potatoes in microwave steam bags; 4 tablespoons salted butter, melted; 1/2 cup light brown sugar, packed; 1/2 cup heavy cream, at room temperature; 1/2 cup all-purpose flour; 2 large eggs, separated, whites whisked to almost stiff peaks; 2 cups mini marshmallows