Rinse the shrimp and lay them out on a paper towel-lined tray. Pat them dry. Prep the other ingredients and set them next to the stove. (This is a FAST recipe and you need to have everything ready to go when you begin.) Set an empty plate next to the stove.
Heat a large stainless steel pan over medium-high heat. Add 1 tablespoon of oil and when it is hot, add the shrimp. Spread the shrimp across the pan and sprinkle with about a ¼ teaspoon of salt and a smaller amount of pepper. Let the shrimp cook for about 1 minute, just until the side touching the pan begins to turn pink.
Stir and then quickly flip the shrimp to the other side. Sprinkle again with salt and pepper. Cook about 1 minute longer, just until pink and barely cooked through. Take care not to overcook. Remove from the pan to the plate.
Add the remaining oil to the pan and then add the zucchini. Stir to coat and then sprinkle with the remaining salt and pepper. Cook for 2-3 minutes, until the squash barely begins to soften.
Add the butter along with the garlic and scrape up any browned bits from the bottom of the pan. Continue to cook for another minute or two, until the butter has melted and the pan is fragrant.
Return the shrimp to the skillet, along with the lemon juice. Stir to mix and then sprinkle with parsley. Serve immediately.