Roast the Foundation: Preheat your oven to 180°C (FAN). Toss your scrubbed and chopped beets, halved shallots, and whole garlic cloves in a baking dish with olive oil and salt.
The Foil Secret: Cover the tray tightly with foil. This steams the vegetables in their own juices, making them soft and tender without burning. Bake for 15 minutes.
The Feta Melt: Remove the tray, add your block of feta, and re-cover with the foil. Return to the oven for another 15–20 minutes until the cheese is soft and the veggies are fork-tender.
Pasta Prep: While the veggies roast, boil your rigatoni in salted water. Pull it one minute before the packet instructions suggest. Crucial: Save at least two large ladles of that starchy pasta water!
The Blend: Transfer the roasted veggies and feta into a blender. Add the lemon juice and the reserved pasta water. Blend until it transforms into a silky, fuchsia-pink velvet.
The Marriage: Pour the sauce over your drained pasta in a pan. Simmer on low heat for a few minutes until the sauce thickens and hugs the rigatoni perfectly.