PRETZEL CRUST

1. Preheat the oven to 325° F. Lightly grease a 9" removable bottom, round tart pan with butter. Place the tart pan on a baking sheet.
2. Pulse the pretzels in a food processor until they are finely ground, with some larger pea-sized chunks remaining. Pour into a large mixing bowl.
3. In a small saucepan, melt the butter over low heat. Continue to heat, stirring frequently, until the butter starts to foam up and brown bits begin to form. Whisk in the brown sugar and stir until fully dissolved. Remove from heat and set aside.
4. Pour the butter mixture over the ground pretzels and stir to combine. The mixture should look like wet sand. Transfer the crumb mixture into the prepared tart pan and use a spatula to spread the mixture evenly into the pan and up the sides slightly.
5. Bake the tart on the the baking sheet for about 15 minutes, until it starts to turn a deep brown and looks set. Set aside and allow the crust to cool completely.

GRAPEFRUIT MARGARITA FILLING

1. Turn the oven up to 350° F.
2. In a medium sized bowl, whisk together the sweetened condensed milk and the egg yolks until smooth. Add the fresh squeezed grapefruit juice, the lime juice and the tequila and continue whisking until completely smooth.
3. Gently pour the filling mixture into the cooled pretzel crust shell. For that optional pretty pink swirl, gently drizzle about tablespoon of Campari over the top of the filling. Use a wooden skewer to swirl the Campari into the top layer of the filling, creating vibrant pink swirls on the yellow filling. 
4. Bake for 15-ish minutes until the filling is set and doesn't jiggle when you shake it.
5. Place on a cooling rack and allow tart to cool completely. Once cooled, transfer to the refrigerator and allow the filling to set for at least 2 hours before serving.

TEQUILA WHIPPED CREAM

1. Chill the metal bowl and whisk of a stand mixer in the freezer for at least 10 minutes.
2. Pour the heavy cream and tequila into the chilled bowl and whisk on a medium-high speed for about 1 minute. Add the sugar and beat for a couple more minutes until soft peaks form.
3. Chill in the refrigerator until you're ready to serve the tart. If you fancy, use a piping bag and an open star tip to pipe cute little stars on each slice of tart. Otherwise just dollop it right on top just before serving. Serve with a sprinkle of sea salt flakes to balance out the sweet and tart flavors.