You can bake these cookies in a 9-inch cake pan, a 9-inch springform or tart pan. If you don't have any of those, move up to a 10-inch (8-inch will make the cookies too thick). If baked in a 10-inch pan, cookies will be thinner, so cooking time will be less. Watch closely!
1cupgood-quality unsalted butterat room temperature
1 1/2tsp.vanilla extract
1 1/2Tbsp.poppy seeds
1/2tsp.saltreduce to 1/4 tsp. if you used salted butter
Prepare a 9-inch baking pan by greasing lightly with butter and lining the bottom with a round of parchment paper. (*Note: if using a pan without a removable bottom, I find it handy to leave a little 2-inch "tab" on the edge of the round of parchment that's going on the bottom of the pan, to make removal from the pan even easier!). Set aside.
Using an electric mixer, beat the butter and sugar until creamy and smooth, about two minutes. Add the vanilla and beat well.
In a separate medium bowl, combine the flour, poppy seeds, and salt. Add the dry ingredients to the butter mixture and mix until mixture is moistened and comes together into a rough dough.
Press dough evenly into prepared pan, then poke the dough with a fork 8-10 times, evenly around the dough. Cover with plastic wrap and place in the refrigerator for at least 2 hours to chill.
Preheat oven to 300° F. Remove pan from refrigerator and place directly into pre-heated oven. Bake until set and firm, about 40 minutes. (*Note: shortbread should look dry on top. Don't judge by the edges, as they will begin to brown quite early and don't necessarily reflect the done-ness of the rest of the pan. Look for the top of the shortbread to begin to turn ever-so-slightly golden).
Remove from oven and leaving shortbread in pan and using a sharp knife, immediately cut shortbread in to 12 wedges. Leave to cool completely in the pan, then remove shortbread from pan.
*Note: It can be a little tricky to know when the shortbread is done the first time, so if you guessed wrong and your shortbread is undercooked (ie: doesn't have that lovely "sandy" shortbread texture), don't despair. Simply place the wedges on a baking sheet, pop into a 300° F. oven and bake for an additional few minutes to dry them out (8-10 minutes or so, but watch them closely. If they start to brown, pull them out).