Preheat oven to 350 degrees F. Grease or line an 8"X 8" glass baking dish with parchment.
In a stand mixer fitted with the paddle attachment, cream butter and powdered sugar until light and fluffy. Add flour and salt, mix until just combined. Press dough into bottom of the pan.
Bake crust at 350 degrees F for 15-20 minutes or until barely golden.
While crust bakes, prepare filling by blending sugar, eggs, flour, baking powder, lemon juice, and salt in the same bowl until just combined.
Pour filling onto baked crust and bake for an additional 20-25 minutes or until a toothpick inserted in the middle comes out clean.
Remove from oven and allow bars to cool completely to set.
Cut into 16 squares and dust with powdered sugar before serving. Garnish with thin slices of Meyer lemon wedges if desired.