Heat Instant Pot on “Saute” function. Add butter, olive oil, shallots, and garlic. Cook, stirring constantly, until shallots soften, 2-3 minutes.
Add wine and cook, stirring, until wine has reduced slightly, about 1 minute. Turn Instant Pot off.
Add 1 ¼ cups broth to pot, scraping up any brown bits. Crack pasta in half and layer in a criss cross pattern. Add remaining broth and separate strands of pasta as much as possible. Sprinkle with red pepper flakes and then add frozen shrimp to the top, without stirring. Sprinkle with salt.
Secure Instant Pot lid and turn valve to seal. Set on “Pressure Cook” or “Manual” (depending on your model) for 0 minutes (not a typo!). If your Instant Pot model will not accept 0 minutes as a setting, simply press Cancel when you hear the signal that it’s reached full pressure.
Once the Instant Pot has reached full pressure, immediately release pressure by doing a “quick release” and turning valve to vent.
Remove cover and stir in Parmesan cheese, fresh parsley, and lemon juice.
Taste and season with additional salt and red pepper flakes as needed. Serve immediately.
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Notes
If using fresh or thawed shrimp:
Cook pasta as directed above, omitting shrimp. It will only take about 6 minutes to come to pressure instead of 15.
When pasta has finished cooking, remove the lid and stir in shrimp. Leave Instant Pot on warm setting, with the lid on but not sealed, and cook for 8-10 minutes or until shrimp is cooked through (pink and shaped like the letter C), stirring 3 times to ensure shrimp cooks evenly.
Continue with the remainder of the recipe and stir in Parmesan cheese, fresh parsley, and lemon juice.