Preheat the oven to 425 degrees. Coat a baking dish with cooking spray.
Prepare the tomatoes by cutting the top 1 1/2 inches off of the tomatoes, then using a paring knife, cut away and scoop out the center flesh and seeds, leaving the outer layer of the tomato all around to create a tomato bowl. (Keep the tomato insides for another recipe like tomato soup or discard).
Cook the chorizo by heating a skillet over medium-high heat.
Add the chorizo meat, casing removed, to the hot skillet. Cook, stirring often, until the fat is rendered and the chorizo crumbles are golden brown, about 6-7 minutes.
Place the cooked chorizo on a paper towel lined plate to drain excess grease.
Make the cheesy rice filling by adding 1 tablespoon of butter to the hot skillet (or use 1 tablespoon of chorizo grease) then add the flour.
Cook and whisk until it's golden in color and smelling a bit nutty.
Slowly whisk in the milk until well combined and thickened.
Add the cheddar cheese and the Parmesan cheese then whisk until well combined and melted. Add the rice, chopped broccoli, and cooked chorizo; mix well. Taste and season with sea salt and freshly cracked pepper, to taste.
Make the panko mixture by combining the panko crumbs, olive oil, and remaining tablespoon of parmesan cheese; mix until well combined.
Finish by placing the tomatoes in the prepared baking dish then season them with sea salt and freshly cracked pepper, to taste.
Fill the tomatoes with the rice mixture, making sure not to cram it in too tight. Sprinkle the panko mixture on top of each tomato, to taste.
Place into the oven and bake for 20-25 minutes. Remove from the oven and serve. Enjoy!