• Preheat oven to 350°F and line a 9x9-inch pan with parchment paper. Set aside.

Oat Crust

• In a large bowl, combine oats, flour, brown sugar, baking powder, and baking soda. Pour melted butter over the mixture and mix together until crumbly, being careful not to overmix.
• Measure out ½ of the mixture (about 2 cups), and set it aside to reserve for topping.
• Pour the remaining half of the mixture into the lined baking dish. Press firmly into the bottom of the pan.
• Bake 12-15 minutes, or until golden brown. Set aside to cool slightly while you make the lemon filling.

Lemon Filling

• To a large bowl, add sweetened condensed milk, lemon juice, egg yolks, lemon zest, and salt. Mix until smooth and creamy.

Assembly

• Pour the lemon mixture over the top of the baked oat crust.
• Evenly crumble the reserved oat mixture over the top.
• Bake for 20-25 minutes, or until edges are golden brown.
• Let come to room temperature. Then, refrigerate 1 hour before serving.