01 -
Preheat oven to 350°F. Lay parchment in an 8x8-inch pan, leaving edges hanging over for easy lifting.
02 -
Melt butter and stir it together with brown sugar, baking powder, and half the salt. Mix oats and flour in next. Save 1 cup for the top.
03 -
Spread the remaining mixture in the pan. Bake for about 12 to 14 minutes till light brown.
04 -
Combine lemon zest, lemon juice, sweetened condensed milk, and the last bit of salt. Stir until smooth.
05 -
Pour lemon filling on warm crust, scatter saved crumbs on top, and bake for 22 to 24 minutes till edges turn golden.
06 -
Let cool all the way (about 1.5 hours). Chill for 30 minutes in the fridge if you want it firmer. Cut into 12 bars.