Preheat your oven to 250°F.
Slice the grape tomatoes in half lengthwise and place them in a bowl.
Add olive oil, salt, pepper, and a couple of chopped garlic cloves to the bowl, then toss everything together until the tomatoes are well coated.
Arrange the tomatoes cut side up in a single layer on a parchment-lined baking sheet.
Roast in the oven for 90 minutes, or longer if you prefer them more shriveled, up to an additional 29 minutes.
