Restaurant-Style Sweet Potato Casserole Recipe

Ingredients

• 2.5 pounds sweet potatoes
• 1 teaspoon vegetable oil, or as needed
• 0.75 cup dark brown sugar
• 0.5 cup heavy whipping cream
• 0.25 cup melted butter
• 0.25 teaspoon ground cinnamon
• 0.25 teaspoon salt
• 0.25 cup rolled oats
• 2 teaspoons dark brown sugar
• 1 tablespoon all-purpose flour
• 0.125 teaspoon ground cinnamon
• 2 tablespoons cold butter
• 2 cups miniature marshmallows