Preheat the oven to 325F and make sure the convection feature is enabled.
Brush an 8 inch cake pan or mold with melted butter.
In a medium bowl, mix the butter, sugar and vanilla.
Add the flour and mix until it comes together to form a soft dough.
Remove the dough and press into the greased cake pan or mold.
Smoothen the surface using your fingers or a smoother if you have one.
Bake at 325F until the surface is a lighter golden and the edges a slightly deeper golden brown. About 30 minutes or so.
Remove from oven and allow the shortbread to cool completely. It should pull away slightly from the edges. If needed, nudge the shortbread away from the edge using a knife. If using a regular pan, place a board on top of the pan. Holding the pan and board together tightly, flip over. You should feel the weight shift. If not, give it a firm pat.
Use a sharp knife cut the shortbread into 8 wedges.
Serve immediately or store the shortbread in an airtight container.