What step should be taken to ensure the foot of a baked Macaron is properly formed?

To ensure the foot of a baked Macaron is properly formed, allowing the piped mixture to dry a bit before baking is crucial. This step helps to create a skin on the surface of the batter, which ultimately traps air while baking. As the batter heats up, the air expands, pushing the mixture upward and causing the signature foot to form at the base of the Macaron. If the piped batter is too wet, it may not have the proper structure to rise properly, leading to a flat or uneven appearance.

This step contributes significantly to achieving the desired texture and appearance of the Macaron. A higher oven temperature may lead to over-baking or uneven cooking, stirring the mixture continuously while baking can disrupt the rising process, and chilling the mixture before piping can result in a batter that doesn’t spread correctly, both of which would negatively impact the foot's formation. Thus, allowing the piped mixture to dry slightly before baking is essential for successful Macaron-making.