1. Preheat oven to 350 degrees and spray nonstick spray on an 8×8 baking dish.
2. In a large mixing bowl add flour, oats, salt, baking soda, sugar and brown sugar.
3. Add the vanilla and melted better into the dry ingredients and mix until combined. Press half the mixture into the bottom of the baking dish. Bake for 15 minutes.
4. While the crust is baking, mix together the condensed milk, lemon zest, lemon juice, and egg yolks in a medium size bowl.
5. Once the bottom crust is done baking, pour the lemon mixture over the top then crumble to rest of the dry mixture over the top.
6. Bake another 22 minutes. Let cool completely, then refrigerate. These bars can be messy, so they do better if refrigerated or frozen before trying to slice them.