To prepare a sun dried tomato spaghetti sauce, you'll first need to gather your ingredients. Cut the tomatoes in half and remove the seeds. Peel the skin and cut the tomato into small cubes. Add the diced tomatoes to the crock-pot and cook on medium-high heat until they're soft, about 10 minutes. Remove the pot from the heat and add the pasta. Cook until the noodles are al dente and the sauce is thickened, 10 to 15 minutes more.