For the rub: Combine the brown sugar, paprika and salt in a small bowl and massage it into the pork shoulder until well coated. Set aside while you make the BBQ sauce. You could do this a day ahead and keep refrigerated until ready to use.

For the BBQ sauce: In a large saucepan, warm the oil over low heat until hot and shimmering. Add the cumin and fennel seeds; they should splutter upon contact, be careful! Once the spluttering subsides, add the ginger, onions, serrano and a little salt to taste. Saute until they soften, but don't let them get any color. Add the mango puree, lime juice, vinegar, Worcestershire sauce and molasses. Simmer about 5 minutes. Taste and season.

Add the pork shoulder to the saucepan, coating it with the sauce. Cover, and gently simmer until the pork falls apart easily, stirring and turning often, about 3 hours.

Remove the pork from the saucepan and shred it using 2 forks. Return it to the sauce and stir to coat with the sauce. Put a generous spoonful of the pork inside a brioche bun, top with a few slices of pickle and serve. Prepare to have your loved one swoon over you!