Preheat the oven to 350 degrees. Bring a large pot of water to a boil and submerge the whole zucchini into the boiling water. Blanch for 5 minutes or until the zucchini have softened somewhat. Then transfer the zucchini to a pot of cold water.
Meanwhile, heat a large skillet over medium high heat. Remove the bratwurst from their casings and add to the skillet to brown. After a couple of minutes, add in the onion, pepper, garlic and seasonings to the pan and continue to brown and cook until the sausage is cooked through and the onions and peppers have softened. Add in the drained tomatoes and simmer for 5 minutes. Remove from the heat.
Halve the zucchini lengthwise and scoop out the insides as best you can with a spoon or melon baller (if you have a grapefruit spoon, it works great!).
Place the prepped zucchini on a greased baking sheet and fill each zucchini half with the bratwurst mixture. Top each with shredded provolone and place in the oven for 15-20 minutes or until the cheese has melted and the zucchini is cooked through