Prep your base: If using zucchini noodles, lightly salt them and set aside for 10 minutes, then pat dry. For spaghetti squash or cauliflower rice, have it pre-cooked and warmed.
Pat shrimp dry: Blot with paper towels so they sear, not steam.
Season both sides with salt and pepper.
Sear the shrimp: Heat 1 tablespoon olive oil and 1 tablespoon butter in a large skillet over medium-high. Add half the shrimp in a single layer and cook 1–2 minutes per side until just pink and opaque. Transfer to a plate and repeat with remaining shrimp, adding a bit more oil if needed.
Sauté the garlic: Lower heat to medium.
Add remaining butter and olive oil. Stir in garlic and red pepper flakes. Cook 30–45 seconds until fragrant, not browned.
Deglaze: Pour in wine or broth.
Scrape up browned bits and simmer 1–2 minutes to reduce slightly. Stir in lemon zest and juice.
Finish the sauce: Taste and adjust salt, pepper, and lemon. If you want a silkier finish, swirl in another 1/2 to 1 tablespoon butter off the heat.
Return the shrimp: Add shrimp and any juices back to the pan.
Toss 30–60 seconds to warm through. Sprinkle with parsley.
Assemble: Plate over zucchini noodles, spaghetti squash, or cauliflower rice. Spoon extra sauce on top.
Finish with a pinch of Parmesan if you like.