Prepare flax egg by adding flaxseed meal and water to a large bowl and mixing to combine. Set aside for 5 minutes to develop an "eggy" texture.
To the same bowl, add melted dairy-free butter (or oil), almond milk (starting with the lesser amount // 1 cup as recipe is written), pumpkin purée, brown sugar, and pumpkin pie spice and whisk to combine.
Add cornbread mix and flour and whisk until just combined. Let rest for 5 minutes while preheating waffle iron. The batter should be thick, but pourable. If too thick, add more milk and whisk to combine. If too thin, add additional flour and whisk to combine.
Spray waffle iron with non-stick pray and pour 1/3 cup measurements onto the griddle (if using a Belgian waffle maker, use 2/3-1 cup batter per waffle). Close and cook according to manufacturer instructions (should be about 3 minutes for thin waffles or 5-6 for Belgian).
Serve warm topped with dairy-free butter and maple syrup (optional). Non-vegans can opt for real butter and honey or maple syrup.
*The amount of almond milk is discretionary depending on the brand of corn mix you use. If it appears too thick, simply add a bit more. And if it's too thin, scale back or compensate with more flour. This recipe is fairly forgiving so you should be fine either way. *Gluten-free version: we tested this recipe with Trader Joe's Gluten-Free Cornbread Mix and our DIY Gluten-Free Flour Blend and found that it did work, but produced a less favorable, slightly gummy texture. If not vegan or egg-free, we would suggest using a chicken egg instead of a flax egg for improved texture. *Nutrition information is a rough estimate.