Steam the broccoli florets. Set aside and allow them to cool for a few minutes.
Chop the broccoli to ½ - ¼ inch pieces and place in a mixing bowl. Add the cheeses, 1 egg, ⅓ cup breadcrumbs, salt, and pepper to the mixing bowl.
To mix, use a clean hands or a spatula. The broccoli should break down and fully blend with the cheese leaving smaller chunks.
Roll the broccoli mixture into ping pong ball sized pieces. Place on a plate and chill in the fridge for 45 minutes. The bite can be made a day in advance and stored in the fridge.
Once ready to cook the bites, remove the from the fridge. Set up breading stations in a line starting with flour and cornstarch, 1 beaten egg + 1 tbsp of water, and then the breadcrumbs.
With your left hand dredge bites in the flour. Transfer to your right hand and dip it in the egg and then the panko. Press the breading into the bites so it is evenly coated. Place bite back on the plate. Repeat with remaining broccoli bites. Keeping one hand dry will be helpful to reduce sticking, and make the breading process more efficient.
Add oil to the cast iron skillet. You want there to be about2 inches of oil in the bottom. If you are using a smaller or larger skillet adjust amount accordingly. Heat oil oven medium high heat. The oil will sizzle if you sprinkle a few breadcrumbs in it when it is ready. Do not add the broccoli bites too soon.
Place bites in the pan using tongs. Keep them from touching so the pan is not too crowded and bites can cook evenly. Depending on the size of the pan you may need to do two batches.
Cook broccoli bites 90 seconds per side. Gently flip the bites, but if the breading begins to stick allow them a little more time.
Remove broccoli bites from the pan and place on a paper towel lined plate. Lightly sprinkle with salt. Serve immediately with ranch dipping sauce.