Place 3/4 cup butter and sugar in a large bowl and beat about 2 minutes.

Add the egg and vanilla extract, and beat for 2 minutes.

In a small bowl, whisk together the flour, baking powder and salt.

Add half of the flour mixture to the sugar-butter mixture, combine, and then add the remaining half.

Flour a clean surface and roll out the dough to 1/2" thickness, in the shape of a large rectangle. (You can do this in two batches, if desired.)

Brush the remaining 1/4 cup of butter on the dough (you may use slightly less, but make sure all of the dough is buttered).

In a small bowl, combine the brown sugar and cinnamon and sprinkle all over the cookie dough.

Roll the cookie dough into a log, long end to long end.

Refrigerate for 1 hour or overnight.

Preheat oven to 350F and remove the cookie dough log from the fridge.

Line two cookie sheets with parchment paper or silicone liners.

Trim off the edges (about 2-3") and discard. Slice the remaining dough into 1/4" thick slices.

Place the slices on a parchment paper-lined cookie sheet (or silicone mat-lineat least 1" apart.

Bake for 8-12 minutes, until just slightly golden on the edges.