Make the dough

1. Preheat the oven to 350 degrees
2. In a mixer fitted with a paddle attachment, cream together butter and powdered sugar
3. Scrape down the butter in between mixing
4. Add in egg and vanilla extract to the butter mixture
5. Add the crushed pretzels and flour; mix until fully combined
6. Remove the dough from the mixing bowl and lightly knead on a floured surface until smooth
7. Form the dough into a ball and wrap with plastic wrap and refrigerate for 1 hour or overnight
8. Once the dough is chilled, roll the dough out on a floured surface to 1/8 inch thick
9. Place the dough in a 9” round or rectangle tart pan and press down the bottom and sides of the tart to create an even and smooth shell
10. Refrigerate the shell for another 30 minutes
11. Bake the shell for 15-20 minutes or until dough is cooked through

Make the Butterscotch Filling

1. In a small bowl, whisk egg yolks; set aside
2. In another small bowl, whisk together the cornstarch, flour, salt and milk; set aside
3. Using a large saucepan, melt the butter over low heat until it turns a light brown color; stir constantly so that it doesn't burn.
4. Add the brown sugar to the butter mixture and whisk until melted
5. Slowly add boiling water to the butter and sugar mixture to create a caramel, it will bubble a lot so pour it slowly while whisking
6. Add the flour and milk mixture to the caramel mixture and stir on low heat until it begins to boil
7. Once the mixture has thickened, add a few tablespoons of the butterscotch mixture to the egg yolks, constantly whisking and then pour the egg yolks back into the saucepan with the butterscotch
8. Continue whisking over low heat until the butterscotch begins to boil and thickens
9. Remove the butterscotch filling from the heat and add in the vanilla extract
10. Pour the butterscotch custard into the pre-baked tart shell
11. Place a piece of plastic wrapped pressed on the custard until cooled and ready to top with whipped cream
12. Refrigerate until ready to garnish and serve

Brown Sugar Whipped Cream

1. In a mixing bowl with whisk attachment, whisk the heavy cream until it starts to thicken and create a ribbon texture
2. Add in the brown sugar to the heavy cream and continue whisking until the cream is smooth and stiff enough to hold its shape (do not over whisk)
3. Once the pie is cooled, spread the whipped cream over the top of the butterscotch custard
4. Sprinkle crushed pretzels around the edge of the whipped cream
5. Refrigerate until ready to serve
6. Enjoy!