1-First Step: Prep and cook the sweet potatoes Place the 4-5 large sweet potatoes in a large pot and add enough water to cover them halfway. Bring to a boil over high heat, then lower the heat to a simmer. Cook until the sweet potatoes are tender when pierced with a fork, about 20 to 40 minutes depending on size. Drain the potatoes and let them cool enough to handle. Peel the skins and transfer the flesh to a large mixing bowl.

2-Second Step: Make the filling Add the following to the bowl with the sweet potatoes: 3 large eggs, 1/2 cup evaporated milk (or cream/half and half), 1 teaspoon vanilla, 1/2 cup sugar, 1/2 teaspoon salt, and 1/4 cup melted butter. Use a potato masher to break down the potatoes until mostly smooth. For a finishing texture, mix the mashed sweet potatoes on low with an electric mixer for about 45 seconds until smooth and airy. If you need to adapt for dietary preferences, swap evaporated milk with full-fat coconut milk for dairy-free, or use flax eggs (1 tbsp ground flax + 3 tbsp water per egg) for a vegan version.

3-Third Step: Transfer to casserole dish Lightly grease a 9×13-inch casserole dish. Spread the sweet potato filling evenly into the dish, smoothing the top with a spatula. At this point you can refrigerate the filling for up to 1-2 days; store the topping separately. If chilling, let the filling sit at room temperature for 30 minutes before adding the topping and baking.

4-Fourth Step: Prepare the pecan topping For the pecan streusel, combine 1/4 cup flour and 1 cup brown sugar in a bowl. Stir in 1 cup chopped pecans. Cut in 3 tablespoons butter using a fork or pastry blender until the mixture is crumbly and well combined. Sprinkle the pecan streusel evenly over the sweet potato filling.

5-Fifth Step: Bake (pecan topping) Preheat the oven to 350°F. Bake the casserole with the pecan topping for 35 to 40 minutes, until the topping is golden and the filling is heated through. If you like a slightly deeper caramelization, place the casserole on a middle rack and check it at 30 minutes so the streusel does not over-brown.

6-Alternate Fifth Step: Marshmallow topping For a marshmallow finish, bake the casserole uncovered for about 20 to 25 minutes to heat the filling. Remove from the oven, scatter 3 to 4 cups miniature marshmallows over the top, then return to the oven for 5 to 10 minutes until the marshmallows are puffed and golden. Keep a close eye during this second bake, as marshmallows brown quickly.

7-Final Step: Serve and optional split-topping For variety, try a split casserole: top half with the pecan streusel and half with marshmallows. Bake using the times above for each topping (pecan side full bake, marshmallow side add marshmallows in the last 5 to 10 minutes). Let the casserole cool slightly before serving. This sweet potato casserole serves 8 to 10 as a side and pairs well with roasted meats or a simple green salad.