How long do you mix puff pastry in a mono high speed mixer?

You should not mix puff pastry in a high-speed mixer, even a mono one.

Here's why:

* Over-Development of Gluten: High-speed mixing will over-develop the gluten in the flour, leading to a tough, chewy pastry instead of the light and flaky texture you want.

* Loss of Layers: The rapid movement of the blades will tear through the delicate layers of butter and dough, compromising the puff pastry's structure.

The Best Way to Mix Puff Pastry:

Puff pastry is best made using a gentle, folding technique. This allows the butter to stay in layers and creates the desired flakiness.

Here's a general guide for making puff pastry by hand:

1. Chill: Keep all ingredients cold, especially the butter.

2. Combine: Mix the flour, salt, and water quickly, forming a dough.

3. Encase: Roll out the dough into a rectangle. Place a sheet of cold butter in the center. Fold the dough over the butter, creating a book-like shape.

4. Fold and Chill: Fold the dough in thirds (like folding a letter) and chill for at least 30 minutes.

5. Repeat: Repeat the folding and chilling process several times for the best results.

If you need to use a mixer, consider a stand mixer with a paddle attachment and use a low speed setting to avoid over-mixing. However, even then, it's best to avoid using the mixer for the final folds and to focus on manual folding for the best results.