Make the sugared pecans first. Melt butter in a small frying pan over medium heat. Cook until it starts to turn brown and smells nutty, about 3-5 minutes. Add pecans and brown sugar and stir to evenly coat. Cook for 2 minutes, stirring constantly until mixture caramelizes. Remove from heat and allow to cool on wax or parchment paper.
Whisk the flour, baking powder, baking soda, salt and pumpkin pie spice in a large bowl. Whisk the sugar and egg yolks in a separate medium-sized bowl. Then whisk in pumpkin puree, Greek yogurt and milk. Finally, whisk in the melted butter. Pour the pumpkin mixture into the flour mixture and stir with a rubber spatula until just combined. Don’t worry if it’s lumpy. Beat the egg whites with a mixer until stiff peaks form, then gently fold into the batter.
Preheat a waffle iron. If it’s not nonstick, grease it. Spoon in the batter and cook until golden brown.
Serve with butter, maple syrup and sugared pecans.
Note: You can keep waffles warm in a 250 degree F oven (directly on the rack) until serving. To save time, feel free to buy sugared pecans. The ones at Trader Joe’s are really good too!