First of all, make the bell pepper pesto (recipe here).
Bring a large saucepan of salted water to a boil. Add a drizzle of olive oil to prevent paccheri from sticking and cook the pasta according to the package’s instructions (about 13-14 minutes).
Mix together ricotta and pesto in a bowl, using a spoon. Salt at your taste.
Drain the pasta. Preheat oven to 220°C.
Stuff each pacchero with the mixture using a teaspoon and arrange it vertically on the baking tray.
Once the baking tray is completely filled, top with grated cheese and bake for 15 minutes.
Sprinkle with chopped chives before serving.