Start by boiling a pot of water and toss in the capellini. When it is ready, you will see it soften and swim gracefully through the water. Give it a stir so it does not clump together. Avoid overcooking or you will get mushy strands.
In a bowl, whisk together the olive oil, reserved caper brine, red pepper flakes, minced garlic, lemon zest, lemon juice, salt, and black pepper. Enjoy the zesty aroma filling your kitchen. Make sure you have a nice mix, as uneven flavors will leave it flat.
Add the halved cherry tomatoes, spinach, capers, and basil to the pasta. It should look vibrant and colorful, inviting you to dig in. Gently toss everything to mix so the dressing coats every bit. Be careful not to squish those tomatoes; they should stay intact.
Sprinkle the grated parmesan cheese over the top. The creaminess will add richness, making this salad feel indulgent. Toss it lightly again but avoid overmixing; you want that cheesy goodness distributed without breaking up the pasta or causing a mess.
Transfer your lemon capellini salad to bowls and dig in. Ideally, it should be enjoyed right away, before the pasta absorbs too much oil. If there are leftovers, add a bit of cooking water or fresh veggies when you serve it again to keep it lively.