Preheat oven to 350F
Butter and line a 13x9 baking sheet with parchment paper
In a large bowl beat the butter with a mixer until soft and fluffy
To the butter add the brown sugar and salt. Beat until well incorporated
Add the 2 cups of flour and beat with mixer until a cohesive dough forms
Pinch chunks of dough and drop onto the baking sheet. Using your fingers which you can intermittently dip in the flour, press the dough into the pan until bottom is covered. Make it on the thinner side and as uniform as you can.
Spread the jam evenly over the crust
Place strawberry slices evenly on top of the jam
In a medium bowl, mix together the cream cheese, lemon zest, lemon juice, vanilla extract, granulated sugar, whole egg, egg yolk, and 1 Tbsp of flour until well blended and creamy
Pour custard batter evenly over the strawberries, tilting the pan to cover them evenly.
Bake for 25-30 minutes until barely set
Cool for 1 hour, then chill for another 2 hours in the refrigerator before cutting into even squares
Enjoy!