Preheat your oven to 350°F and butter a 9x13-inch baking dish generously. Spread the cubed day-old waffles evenly across the bottom, breaking larger pieces into bite-sized chunks that'll nestle together snugly and create even layers.

Whisk together the eight eggs, milk, pumpkin puree, maple syrup, pumpkin pie spice, vanilla extract, and salt in a large bowl until completely smooth and no pumpkin streaks remain. This custard mixture is the soul of your dish, so blend thoroughly for best results.

Pour the custard mixture evenly over the waffle cubes, pressing down gently with the back of a spatula to ensure thorough saturation from top to bottom. Let this sit for 10 minutes while you prepare the topping—this crucial resting period allows the waffles to absorb the liquid properly and ensures even cooking.

Make the pecan streusel by combining melted butter, brown sugar, cinnamon, and chopped pecans in a small bowl, mixing until crumbly and fragrant. Scatter this mixture evenly across the entire top of the cozy pumpkin spice waffle bake recipe, distributing the pecans so every slice gets some crunch.

Bake for 40-45 minutes until the custard is set but still slightly jiggly in the very center when gently shaken. The edges will puff up slightly and turn golden brown, signaling that the eggs have cooked through properly.

Remove from the oven and let cool for 5-10 minutes while you prepare the simple glaze by whisking together powdered sugar, heavy cream, and vanilla extract until pourable consistency is reached.

Drizzle the glaze generously across the warm spice waffle bake, allowing it to pool in the pecan crumbles. Serve immediately while the casserole maintains its warmth and the glaze is still glossy and slightly warm.