Warm 2 cups milk (to between 100 and 110 degrees F) in a small saucepan over medium heat.
Remove from heat and sprinkle in the yeast. Let stand for 5 to 10 minutes until the yeast begins to foam up. (Working with yeast can take some practice, but it must foam up a little for your waffle batter to rise properly - see image at bottom of post.)
Melt the butter, honey, and vanilla together in a separate bowl or saucepan.
Meanwhile, in a large bowl whisk together the flour, cinnamon, and salt. Make a well (hole) in the center, and gently whisk in the eggs. Add the seltzer water and whisk a little more (will foam up), and then while continuously whisking, pour in the melted butter mixture and then the milk mixture and stir until smooth.
Cover with plastic wrap or a kitchen towel and let stand at room temperature for 1 to 2 hours until the dough almost doubles in size. I prefer to make my batter the night before and let it rise in the fridge overnight.
Cook in a waffle iron (in batches) according to manufacturer's directions.
Garnish with homemade unsweetened whipped cream (simply shake heavy cream in a jar until you no longer hear the liquid hitting the sides), pure maple syrup and fresh berries.