01 -
Warm up your oven to 350°F (175°C) and coat an 8x8-inch baking dish with cooking spray.
02 -
Throw the flour, oats, salt, and baking soda together in a big bowl.
03 -
Add both white and brown sugars, stirring until they're mixed throughout.
04 -
Pour in the melted butter and vanilla, then stir everything until you get a nice crumbly texture.
05 -
Push half the mixture down firmly into your greased pan to make a solid base.
06 -
Let it bake for 15 minutes until it feels a bit firm but isn't brown yet.
07 -
While that's in the oven, blend the condensed milk, lemon peel, juice, and egg yolks until they're smooth.
08 -
After removing the base, pour your lemon mixture on top. Scatter the leftover crumbles across the surface.
09 -
Put it back in for another 20-22 minutes until the top turns slightly golden and the filling sets up.
10 -
Let it cool down completely, then stick it in the fridge for at least 2 hours until firm.
11 -
For tidy pieces, make sure they're super cold or pop them in the freezer briefly so the filling doesn't run.