banana shortbread
from vanillasugarblog.com
inspired from america’s test kitchen

½ cup old-fashioned rolled oats
1 ½ cups (7 ½ ounces) unbleached all-purpose flour
¼ cup cornstarch
2/3 cups + 1 TB confectioners’ sugar
½ teaspoon table salt
2 sticks (8 oz) unsalted butter, room temp
1 ½ bananas, wicked ripe, mashed w/ juice of ½ lemon

Pulse oats in spice grinder or blender until reduced to fine powder, about ten 5-second pulses (you should have ¼- to 1/3 cup oat flour).
In bowl of standing mixer fitted with paddle attachment, mix oat flour, all-purpose flour, cornstarch, sugar, and salt at low speed until combined, about 5 seconds.
Add butter to dry ingredients, then add in the banana mixture, and continue to mix on low speed until dough just forms and pulls from sides of mixer wall, 5 to 10 minutes. (I chilled my dough overnight—I think it needs to be chilled at least 2-3 hours before using)
When ready to bake, adjust oven rack to middle position and heat oven to 450 degrees.
Place closed collar of 9- to 9 ½-inch springform pan directly on parchment-lined rimmed baking sheet (do not use the springform pan bottom).
Press dough into collar in even ½-inch thick layer, smoothing top of dough with back of spoon.
Place 2-inch (oven safe) biscuit cutter in center of dough and cut out center. Place extruded round on side of rimmed baking sheet and replace cutter in center of dough. Open springform pan collar, but leave in place. (I did not open collar until see below).
Bake shortbread for 5 minutes, then reduce oven temperature to 250 degrees. (release latch on the collar on springform pan, but don’t take off. Recipe by dawn finicane)
Continue to bake until edges turn pale golden, 10 to 15 minutes longer. Remove tray from oven; turn oven off.
Remove springform pan collar and cutter; score surface of shortbread into 16 even wedges, cutting halfway through shortbread.
Using wooden skewer, poke 10 holes into each wedge. Return shortbread to oven and prop door open with handle of wooden spoon, leaving 1-inch gap at top.
Allow shortbread to dry in turned-off oven until pale golden in center (shortbread will be firm but giving to touch when ready), about 1 hour.
Transfer baking sheet to wire rack; cool shortbread to room temperature, at least 2 hours. Cut shortbread at scored marks to separate and serve.