Start by adding the butter and olive oil into the pan on medium heat.
Add the diced onions and cook for 3-4 minutes or until translucent and slightly tender.
Incorporate the garlic and cook just until fragrent.
Next, add the tomatoes and basil. Mix, and season with kosher salt & fresh ground pepper.
Let simmer for about 20-30 minutes and then taste to adjust the seasoning.
Blend for smoother texture if desired.
Enjoy!
Video
Notes
Go low and slow on the onions: Let them soften gently until sweet and translucent before the garlic goes in. This builds the base flavor the whole sauce leans on.
Don't burn the garlic: It only needs a minute — the second it smells fragrant, move on. Burnt garlic turns the whole pot bitter.
Taste as it simmers: After 20-30 minutes, taste and adjust. A pinch of sugar softens acidic tomatoes; a little more salt wakes everything up.
Smooth or rustic, your call: Blend it for a silky sauce or leave it chunky for a heartier texture — both are right.
Storage: Keeps 4-5 days in an airtight container in the fridge and freezes beautifully for up to 3 months. Make a double batch — you'll be glad you did.