In the bowl of an electric mixer fitted with the paddle attachment, combine flour, salt, and malt powder.
Add butter.
Mix until combined. There should still be some small chunks of butter.
Add lemon juice and water.
Mix on low only until it comes together.
Turn out onto work surface and form into a rectangle.
Wrap in plastic wrap.
Refrigerate for 20 minutes.
Roll into a 6-inch x 12-inch rectangle.
Fold the bottom third of the dough up and the top third down, like a letter.
Turn the dough 90°.
Repeat the rolling and folding process.
Re-wrap in plastic wrap.
Return to refrigerator for 20 minutes.
Repeat 2 more times.
While dough is chilling the final time, heat oven to 400℉/200℃.
Spray the bottom only of the tart pan with cooking spray.
Roll dough out into an 7-inch x 16-inch rectangle.
Fit into prepared tart pan.
Press lightly into the bottom, corners, and grooves.
Trim any excess.
Line with parchment paper.
Fill with pie weights.
Bake for 10 minutes.
Remove from oven and set aside.
Reduce oven temperature to 350℉/177℃.