What is the first step in preparing Puff Pastry?

The first step in preparing puff pastry involves combining flour and salt. This foundational step is crucial as it sets up the structure of the pastry. The incorporation of flour and salt helps to create the right consistency for the dough, ensuring that it can support the layers that will develop during the folding and lamination process.

Combining flour and salt is important for the overall flavor and texture of the pastry. The salt not only enhances the flavor but also strengthens the gluten in the flour, which provides the necessary elasticity for the dough. It's essential for achieving the desired flaky texture once the pastry is baked.

The other options focus on later steps in the puff pastry preparation process. For instance, whisking egg yolks is typically related to enriching the dough or for an egg wash, while melting butter would occur after the dough is formed to incorporate into the layers. Adding water is a part of hydrating the dough, which follows the initial mixture of flour and salt. Thus, starting with the combination of flour and salt is the correct foundational approach when preparing puff pastry.