Preheat the oven to 350°F (175°C) and grease an 8x8-inch baking pan with baking spray.

In a large bowl, combine the flour, oats, salt, and baking soda.

Stir in the granulated sugar and brown sugar.

Mix the melted butter and vanilla extract, then add them to the dry ingredients. Stir until well combined.

Press half of the mixture firmly into the bottom of the prepared pan.

Bake for 15 minutes.

While the crust is baking, whisk together the condensed milk, lemon zest, lemon juice, and egg yolks.

Once the crust is done, pour the lemon filling over it. Sprinkle the remaining crumble mixture evenly over the top.

Bake for an additional 20–22 minutes, until lightly golden.

Allow the bars to cool completely, then refrigerate until firm.

For cleaner slices, chill the bars thoroughly or freeze briefly before cutting to prevent the filling from oozing.

Optional: For an extra treat, dip the bottom half of the frozen bars in melted white chocolate. Place them on a wax paper-lined baking sheet and refrigerate until set.