Pierce the squash all over with a knife (~10 pokes). Microwave whole on high 10–12 minutes, flipping halfway, until it gives when pressed. Let sit 5 min, then cut in half, scoop out seeds, and fork the strands into a bowl. Season with salt and a drizzle of olive oil.
Heat olive oil in a large skillet over high heat. Add asparagus, season with salt and pepper, cook 3–4 min until just tender with a little char. Push to the side.
Add garlic to the pan, 30 seconds, then add shrimp in a single layer. Season with salt, pepper, and red pepper flakes. Cook 1–2 min per side until pink. Don't overcook.
Add the squash strands to the pan. Add pesto, toss everything together over low heat for 1 minute. Taste, adjust salt. Top with Parmesan and serve.
| Step | Time |
|---|---|
| Squash in microwave (hands-off) | 10–12 min |
| Prep shrimp, asparagus, garlic (while it cooks) | parallel |
| Stovetop cook | 8–10 min |
| Total active time | ~15 min |