Preheat oven to 425 degrees F. Place chopped bread onto a baking sheet and set aside.
Over medium heat, pour olive oil into an oven safe dutch oven and allow oil to warm. Combine shallots and onion and saute for 5 minutes, then add thyme, garlic, salt, and pepper and cook for an additional 2-3 minutes, until fragrant.
Remove from the heat and add heirloom tomatoes. Cover with a lid and put into oven to roast for 25-30 minutes. Reduce the oven temperature to 375 degrees F and add the baking sheet with the bread into the oven and bake for 25 minutes, until hard and slightly browned.
Once removed from the oven, the tomatoes should be soft and juicy if pressed. Add everything into a blender along with the fresh basil leaves and blend until smooth.
Pour mixture back into the dutch oven over low heat and add coconut milk and pesto, mix together until fully incorporated. Bring to a simmer and cook undercovered for 25 minutes, stirring occasionally. Add parmesan cheese and generously season with salt and pepper, taste and adjust as needed.
Remove the baking sheet from the oven and place the bread into a large mixing bowl. In a food processor, add basil, rosemary, pesto, olive oil, garlic cloves, Parmesan cheese, salt and pepper. Pulse until chunky. Pour on top of the bread and toss to coat, ensure every piece is covered.