The night before, in a large bowl, dissolve the yeast in the water and let stand for 5 minutes. Stir in the milk, butter, maple syrup, salt, sugar, and vanilla. Add the flour and stir until the batter is smooth.
Cover the bowl with plastic wrap and let it sit overnight at room temperature.
The next morning, beat the eggs together with the baking soda and whisk them into the batter until combined.
Cook the waffles according to the manufacturer’s instructions until golden brown, 4 to 6 minutes.