Preheat oven to 350 degrees.
Line 8x8 pan with foil & spray with cooking spray. Set aside.
Microwave butter in 30 second increments to melt. Set aside for about 5 minutes to let cool to room temp.
Once cooled a bit- add your egg, brown sugar & vanilla. Whisk to combine.
Add flour & stir until just combined. Do not over mix.
Fold in crushed pretzels.
Transfer to prepared pan- press down into corners & smooth out.
Drizzle your marmalade over the top in whatever design you like.
Bake 28-33 minutes- until center is set. Until toothpick test is mostly clean.
Don't ever bake- will firm as it cools.
Cool in pan at least 30 minutes. Store in air tight container for up to 1 week if they are not gone before then.