Bring a large pot of salted water to a boil.
Add the ravioli and the whole Roma tomatoes to the boiling water and cook the ravioli according to package directions; cook the tomatoes until their skins burst (about 6 minutes).
If the tomatoes do not burst after 6 minutes, cut an "X" in the bottom and boil about 2 minutes longer; then remove tomatoes and let cool until you can handle them, peel, seed, and dice.
When ravioli is done, drain in a colander and reserve; set aside.
While the pasta cooks, place the drained sun-dried tomatoes in a food processor and pulse until finely minced, or finely chop by hand.
In a large deep skillet over medium heat, melt the butter. Add the minced garlic and sauté about 30 seconds until fragrant.
Add the flour and cook, stirring constantly, for 1½ minutes to form a roux.
Slowly whisk in the milk and heavy cream until smooth, then add the minced sun-dried tomatoes and whisk to break up any clumps.
Season the sauce with salt, freshly ground black pepper, and red pepper flakes to taste. Bring to a gentle boil, stirring constantly, until the sauce thickens, then reduce heat.
Stir in the shredded Parmesan and the diced Roma tomatoes and cook, stirring frequently, until the cheese melts and the sauce is cohesive. Thin with up to 1/4 cup additional milk if desired.
Add the drained ravioli to the sauce and gently toss to coat; stir in half of the chopped basil.
Serve the ravioli warm, topped with the remaining chopped basil.
