Whisk the eggs together and add in the milk.
Next, add as much salt and pepper as you like along with the paprika.
Put the cooked pasta in a large bowl, and stir the mozzarella through.
Add the egg/milk mixture and stir until everything is evenly distributed.
Melt 20g (1½ tbs) butter in a pan.
Finely chop the onion, and then add to the melted butter.
Fry until the onion softens (a couple of minutes), and then add the garlic and cook for a further couple of minutes.
Remove the onion/garlic with a slotted spoon, leaving most of the butter in the pan. Stir into the cooked pasta mixture.
Add the remaining 20g (1½ tbs) butter to the pan and when melted, pour in your frittata mixture.
Cook on a moderate heat (not too high) for around 10 minutes. The middle will be almost cooked (but will still jiggle a little) and the edges will firm up (you can test this by pushing a spatula down the sides).
Take a large plate, and place it over the pan (the plate needs to be bigger than the pan).
Gently turn the pan and plate upside down, and then carefully slide the frittata back into the pan.
Return to the heat and cook for a further five minutes or so.
When ready, sprinkle with a little parmesan and chives (if you like). Serve warm or cold. Enjoy!