Step 1

Heat oven to 350°F. Line an 8×8-inch pan with parchment paper or foil, leaving an overhang. Spray with nonstick spray.

Step 2

Mix flour, oats, salt, and baking soda in a bowl.

Step 3

In another bowl, whisk melted butter, brown sugar, and vanilla. Stir in dry ingredients.

Step 4

Set aside ¾ cup of the dough for topping. Press the rest into the pan.

Step 5

Bake for 10 minutes.

Step 6

Whisk together condensed milk, sour cream (or yogurt), egg yolk, lemon juice, zest, and vanilla.

Step 7

Pour filling over the baked crust and spread gently.

Step 8

Crumble the reserved dough on top.

Step 9

Bake for another 17-20 minutes until golden and set.

Step 10

Cool & Serve: Let it cool completely before slicing. Enjoy!