Preheat the oven to 450 degrees Fahrenheit and line a rimmed baking sheet with foil.
Using your fingers, tear open the peeled tomatoes over a large bowl and remove the liquid and seeds. Strain and discard the seeds using a fine mesh strainer and reserve the liquid. Spread the tomatoes into a single layer over the prepared baking sheet and sprinkle with dark brown sugar.
Bake in the preheated oven for about 30 minutes, or until most of the liquid has evaporated and the tomatoes start to turn a darker color. Once done, scrape the tomatoes into a medium bowl and set aside to cool slightly.
While the tomatoes are baking, melt the butter in a pan over medium-high heat. Add the diced onion and tomato paste and cook until softened. Add the white wine and orange juice and cook until slightly reduced. Add ½ cup of the reserved tomato juice to the pan and stir until combined. Add the roasted tomatoes, cover, and simmer for 5 minutes over low heat.
Add the onion and roasted tomato mixture to a blender. Purée until smooth.
Wipe out the pan and return the tomato mixture to the pan. Bring the mixture to a simmer, then add the heavy cream. Season with salt and pepper, to taste. Remove from heat, cover, and set aside.