Select browning and add a tablespoon butter and olive oil to the pressure cooking pot.
When butter has melted, add onion, thyme, oregano, salt, and pepper. Stir occasionally until onion has softened. Stir in the carrot and celery.
Move the contents to the side of the pressure cooker. Add the beef and garlic and stir to break up. Saute, stirring occasionally, until the beef is brown on at least one side and the juices have evaporated, about 5 minutes. Pour in the crushed tomatoes.
Close and lock the lid of the pressure cooker. Cook at high pressure for 18 minutes. When beep sounds turn pressure cooker offer and use a quick pressure release. When valve drops carefully remove the lid.
Remove and discard the herb stems. Add the remaining tablespoon of butter to the sauce and stir until melted.
Add the salt and lasagna strips to the sauce in the pressure cooking pot. Pour in enough water to cover the pasta. I added a cup of water. Smooth down the top pieces of pasta so they are submerged.
Close and lock the lid of the pressure cooker. Cook at low pressure for 5 minutes, or half the cooking time indicated on the pasta package. when beep sounds, turn pressure cooker off and use a quick pressure release. When valve drops carefully remove the lid. Taste the noodles and if you'd like them a little softer, cook on simmer until the noodles are tender.
Pour the lasagna into a large serving dish. Sprinkle the mozzarella over the lasagna and stir. Let stand, uncovered for 2 minutes before serving.