Preheat your oven to 400°F and prepare a baking sheet.
Slice the cucumber in half. Place one half on the baking tray, drizzle with olive oil, and season lightly with salt. Roast for 20 minutes at 400°F until tender and browned around the edges.
Chop the remaining fresh cucumber half into bite-sized pieces and set aside.
Once roasted, remove the cucumber from the oven and let it cool completely.
Boil the penne in generously salted water according to the package instructions until al dente, tender with a slight firm bite.