Wash the Roma tomatoes thoroughly. Remove the stems and cut away any bruised or damaged areas.

Cut each tomato into quarters.

Working in batches as needed, add the quartered tomatoes to a blender.

Blend for 12 to 15 seconds, or until the tomatoes are broken down and no large chunks remain.

Place a fine-mesh sieve over a large bowl.

Pour a portion of the blended tomatoes into the sieve.

Use a spoon or silicone spatula to gently move the tomato mixture around the sieve, allowing as much excess liquid as possible to drain into the bowl.

Continue working in batches until all of the blended tomatoes have been strained. This process may take about 10 minutes. Removing excess liquid helps reduce the cooking time.

Transfer the thick strained tomato mixture to a large saucepan.

Place the saucepan over low heat and bring the tomatoes to a gentle simmer.

Cook for approximately 1 hour 50 minutes, stirring regularly and more frequently as the mixture thickens to prevent scorching.

Continue cooking until the tomatoes have reduced to a thick, concentrated paste. The exact cooking time may vary depending on how much liquid was removed during straining.

Remove the tomato paste from the heat and allow it to cool.

Use immediately in your favorite recipe or transfer to an airtight container for storage.