Add the marinara sauce, sliced garlic and sundried tomatoes to a small baking dish and stir together.
Nestle the block of feta cheese into the sauce and sprinkle with chili flakes and dried oregano. Drizzle the feta with olive oil and then bake for 15-20 minutes until the feta is quite soft and the sauce is bubbling just around the edges.
Let cool for a few minutes before garnishing with fresh basil and serving with crostini.
Optional: make your own crostini
Preheat the oven to 400°F. Use a bread knife to slice a baguette into 1-inch thick slices, about 20-24 slices. Place the baguette slices on a parchment paper lined baking sheet. Brush the bread slices with olive oil on one side and place in a single layer on the baking sheet. Bake for 5 minutes, then flip and bake for another 5 minutes until toasted. Set aside.