In a mixing bowl, combine the butter, salt and bread flour. Beat with a wooden spoon until the butter is really soft and well blended. Add the lemon juice and mix until homogenous.
Remove the butter from the bowl. Place on a plastic wrap and form into a 4 x 4" square. Wrap and chill for 30 minutes.
Remove the dough from the refrigerator. Remove the plastic wrap and place on a LIGHTLY floured surface. Mark an "X" on the top of the dough and roll out the ball of dough in 4 places so that it looks like a flower petal with a thick section in the middle. Brush away any excess flour (see above diagram for visual explanation).
Remove the butter block from the refrigerator. While still in the plastic, gently tap the block with the rolling pin to loosen it up a bit. Place the chilled butter square on the thick part of the dough (the center part of the "flower").
Fold the four "petals" over the butter from left to right and from top to bottom to enclose it. Brush away the excess flour between the layers. Make sure it's completely enclosed so that the butter does not come out.
On a lightly floured surface, start the rolling process by gently tapping the center of the dough with the rolling pin. Center to right and then center to left. This helps the butter move through the dough, but prevents tearing the dough. Roll the dough into a rectangle about 7 x 14". Brush off any excess flour and make sure the corners are square.
With the rough side up, fold the dough into 4th (book fold) and wrap in plastic wrap. Chill 30 minutes.
Repeat the process of rolling the dough into 7 x 14" four times using a letter fold (like you would fold a letter to get it into an envelope. So, one book fold, 4 letter folds. After the fifth fold, the dough is ready to be rolled into its final shape.
Now, start the palmers! Preheat the oven to 400F (375F if a convection oven).
On a well SUGARED (not floured) surface, adding sugar to the top of the dough, roll out the dough into a rectangular 8 x 20, using more sugar as needed to ensure that it doesn't stick. Really work the sugar into the surface of the dough.
Turn the dough into a landscape orientation and complete a book fold with the fold going from the top to the center and the bottom to the center. Sprinkle more sugar on top of the fold and then fold the dough over onto itself.
Cut the dough into 3/4" pieces and arrange, cut side up, on a sheet tray . Refrigerate cut palmers on the sheet tray before baking at least 4 hours to give the sugar a chance to start dissolving, which will lead to better caramelization.
Bake 14-16 minutes until you start to see caramelization. Remove from pan, flip over each palmier and continue baking another 7-8 minutes until nice and brown.
Cool to room temperature and store in an airtight container. They can be frozen.