Are regular oats possible to use instead of quick cooking?

Yes, you can use regular oats instead of quick-cooking oats, but they will require a longer cooking time. Regular oats, also known as old-fashioned oats, have a thicker texture and take about 5-10 minutes to cook, whereas quick-cooking oats are thinner and typically cook in 1-2 minutes. Adjust the cooking time and liquid ratio accordingly to achieve the desired consistency.

Can I sub mascarpone for the cream cheese?

Jackie,
It is easy to make regular oats into quick oats in your food processor, just pulse!

I reckon yes, but you'll have to cook the oats for longer and probably with more liquid to get them soft and creamy before proceeding.