Wash the tomatoes thoroughly and cut them into quarters.

Remove the stems and any blemished parts.

Place the quartered tomatoes in a saucepan over medium heat.

Cook for about 30 minutes, stirring occasionally, until the tomatoes are soft and have released their juices.

Remove from heat and let cool slightly.

Blend the cooked tomatoes until smooth.

Strain the blended mixture through a fine-mesh strainer to remove seeds and skins.

Return the strained tomato mixture to the saucepan.

Add salt and olive oil, if using. Simmer on low heat for about 1 to 1.5 hours, stirring frequently, until thickened to a paste consistency.

Let the tomato paste cool completely.

Transfer to a storage container and refrigerate or freeze for later use.