Preheat oven to 325. Lightly grease (I use baking spray) and then line an 8 or 9-inch cake pan (round or square) with parchment paper. (See Café Tips above in post regarding size of the pan.) Line a sheet pan with foil. Set both pans aside.

Combine soft butter, sugar, lemon zest and juice and vanilla in a medium-large bowl. Stir for about 30 seconds until nice and creamy.

Add the flour, thyme leaves and salt. Stir just until all of the flour is incorporated. The dough will be crumbly. Press the dough firmly into the prepared pan to create an even surface. Be sure there are no loose crumbs around the edges of the pan. Sprinkle with the sugar.

Place the cake pan on top of the foil lined sheet pan. Bake for 35-45 minutes until the top is a nice golden brown. (The smaller your pan is, the thicker your shortbread will be and the longer it will take to bake.)

Slide the shortbread onto a cutting board and sprinkle with a bit more sugar, if desired. With a long, sharp knife, cut it into wedges (or rectangles or squares if using a square pan). Transfer pieces to a wire rack to cool completely. Store in an airtight container.

If you prefer your shortbread crisper, place the cooling rack with the cut pieces on a sheet pan and return return to the oven for 5 minutes then cool completely on the rack.

Garnish when serving with a few more fresh thyme leaves, if desired.