Preheat the grill to medium-high heat, around 400°F (205°C). Slice fresh pineapple into rings, about ½ inch thick. Grill the pineapple for about 3-4 minutes per side until grill marks appear and it softens.

In a cocktail shaker, add a few slices of jalapeño and muddle gently for 5-10 seconds to release its oils without over-muddling.

Chop the grilled pineapple into smaller pieces and add to the shaker with the muddled jalapeño. Pour in 2 ounces of whiskey, 1 ounce of fresh lemon juice, and ½ ounce of simple syrup.

Fill the shaker with ice and shake vigorously for 15-20 seconds until the outside of the shaker becomes frosty.

Strain the mixture into a glass filled with fresh ice, ensuring a smooth pour without jalapeño bits.

Garnish with a slice of grilled pineapple and a thin jalapeño slice on the rim. Serve immediately and enjoy!