Set Instant pot to saute setting. When hot, add butter and then chopped onion and garlic. Cook, stirring frequently for 2 minutes, until translucent.
Press cancel and then add all group-2 ingredients and stir well. Close and lock lid (making sure that valve is set to sealing). Select manual setting (or pressure cooker) for 7 minutes.
After 7 minutes, let Instant pot in the warm mode for 10 minutes. Turn valve to venting to release pressure. Open lid, stir group-3 ingredients and serve.
Sauce might look a bit thin as soon as you open lid, but it will thicken in couple of minutes. The sauce will continue to thicken as it cools. Just stir some water to loosen it up.
1. Salt will depend on your taste level and the type of marinara sauce used. I used Prego, tomato basil garlic and used 3/4 teaspoon salt.
2. Please use only canned coconut milk and not coconut milk beverage. I used Chaokoh canned coconut milk <--- shake can well before opening.
3. I used 3-quart size Instant pot.
4. If you want pasta to be al dente, then cook for 6 minutes and then 10 mins of warm instead.