Heat oven to 425 degrees.

Spread the pineapple in an even layer on a baking sheet lined with parchment. In a small bowl, whisk together the cayenne and brown sugar. Sprinkle the mixture over the pineapple. Roast for 15-20 minutes or until the pineapple is golden brown.

Allow to cool to room temperature.

When the pineapple is cool, place it in a blender with the tequila, lime juice, orange juice and salt. Puree until smooth. Transfer the mixture to the refrigerator for 1 hour.

Strain the mixture, if desired. (I did not strain, I like to keep the consistency thick like a smoothie.)

Divide the margarita mixture between four ice filled glasses and serve immediately.