First Step: Prepare Peach Filling Combine 1 tablespoon cornstarch with 2 tablespoons melted butter to form a paste. In a medium saucepan over medium heat, stir together 3 cups chopped canned peaches (or peeled, diced fresh peaches), 1/3 cup granulated sugar, 3/4 teaspoon cinnamon, and 1/2 teaspoon nutmeg. Add in the cornstarch-butter paste and cook, stirring constantly, until the mixture thickens into a luscious filling. Remove from heat and let cool slightly while you make the streusel.

Second Step: Make the Streusel Topping Preheat your oven to between 350-400°F (175-200°C), depending on your recipe variation. Mix 1/2 to 1 cup all-purpose flour, 1/4 to 1/3 cup light brown sugar, 1/4 cup granulated sugar, 1/2 teaspoon cinnamon, and 1/4 teaspoon nutmeg in a bowl. Cut 1/4 to 6 tablespoons cold unsalted butter into the mixture until it becomes crumbly. Spread the streusel on a parchment-lined pan and bake for 9-15 minutes until golden, stirring occasionally for even browning. Cool completely in the fridge to prepare for cake assembly.

Third Step: Prepare the Cake Batter Lower the oven temperature to 325-350°F (163-175°C). Grease and flour a 12-cup bundt pan with butter and flour. In a large bowl, cream together 1 1/2 cups unsalted butter and 2 1/2 cups granulated sugar for 5-7 minutes until light and fluffy. Add 6 room-temperature eggs one at a time, beating well after each addition and scraping the bowl sides. On low speed, add 3 cups sifted cake flour, 1 teaspoon salt, and 1/4 teaspoon baking soda or 2 1/4 teaspoons baking powder in two parts, mixing just until combined. Gently blend in 3/4 to 1 cup sour cream or buttermilk and 1 1/2 tablespoons vanilla extract. Fold in approximately two-thirds of the peach filling carefully to keep peach pieces intact.

Fourth Step: Assemble and Bake Pour half of the batter into your prepared pan. Sprinkle some streusel over the batter, then dollop the remaining batter in spoonfuls on top. Add diced peaches evenly if used separately from filling and finish with the remaining streusel crumb. Bake for 1 to 1 hour and 15 minutes, checking doneness with a toothpick inserted at the center it should come out clean. If edges brown too quickly, tent with foil halfway through baking. Let it cool in the pan for 10-30 minutes before turning out onto a wire rack to cool completely usually about 1 hour.

Final Step: Glaze and Serve Prepare an optional glaze by whisking 1 cup powdered sugar, 1 tablespoon peach preserves, and 1/2 teaspoon lemon juice to smooth consistency (add water if needed). Alternatively, make a cream cheese glaze with cream cheese, butter, powdered sugar, milk, and vanilla extract. Once cake is cool, drizzle glaze over the top, garnish with extra reserved peach filling and remaining streusel. Serve warm or at room temperature, perfect on its own or paired with vanilla ice cream.