Cook pasta according to package directions. Remove pasta through a slotted spoon reserving the cooking water.
Add frozen peas to the hot water to thaw, then remove and add to pasta.
Make pesto by placing basil, garlic, pine nuts, oil, salt, pepper, and Parmesan into a blender or food processor. Blend until smooth. (You may simply substitute with store-bought pesto if desired.)
Dice tomato.
Add pesto and tomato to pasta mixture and stir to combine.
Serve immediately or refrigerate until chilled if preferred; serve grapes on the side.