Heat the skillet over medium heat and add a tablespoon of olive oil. Once shimmering, add the sliced red bell pepper if using, and sauté until tender and slightly crisp, about 2 minutes. Remove and set aside.
Add the butter to the same pan and let it melt over medium heat, filling the kitchen with a rich aroma. Once melted, add the minced garlic and cook until fragrant, about 30 seconds, until it turns lightly golden.
Increase the heat to medium-high and add the shrimp to the skillet, spreading them out in an even layer. Cook for about 2-3 minutes, stirring occasionally, until they start to curl and turn pink.
Pour in the pineapple juice and sprinkle crushed red pepper over the shrimp. Stir gently to coat everything evenly and let the sauce simmer for 2-3 minutes until slightly thickened and the shrimp are fully opaque.
Return the cooked red bell peppers to the pan if using, and toss everything together to combine flavors. Season with salt and pepper to taste, adjusting for balance and spice.
Remove from heat and transfer to a serving dish. Serve hot, garnished with additional red pepper flakes if desired for extra heat. Enjoy the tender shrimp coated in tropical, savory sauce with crispy garlic notes.
