In a medium bowl, whisk together the milk, yeast, and sugar. Let the mixture rest until the yeast becomes frothy, about 5 minutes.

In a large bowl, whisk together the flour and salt. When the yeast mixture is ready, pour it into the bowl of flour along with the egg.

Use an electric hand mixer and beat the batter until it is smooth. You can also use a whisk but an electric mixer is quicker.

Cover the batter and let it rest for 45 minutes to an hour, the batter should become very bubbly and double in size.

Heat a poffertjes pan or large skillet over medium heat. Grease each cup or the surface of the skillet with some of the butter and scoop a heaping tablespoon of batter into each cup. If using a skillet leave a couple inches of space between each poffertjes.

Flip the poffertjes after about 2 minutes of cooking, bubbles should form on the top of the uncooked batter.

Cook another 1-2 minutes until they are all golden brown on both sides then remove from the pan and continue with the rest of the batter.

Serve fresh dusted with some powdered sugar and your favorite sweet breakfast sides!