Preheat oven to 400 degrees

Add cottage cheese and milk in a blender and blend until smooth.

Add cottage cheese mixture to a large bowl. Add in eggs, salt, and pepper and whisk until completely combined. Add 1/2 cup of cheddar cheese and stir into the egg mixture.

Meanwhile, heat a skillet on medium. Add the oil and once it is warm, add in diced onions and cook until translucent. About 2-3 minutes. 

Add in broccoli and cook until broccoli is fork-tender. Approximately 8 minutes. Season with salt. 

Grease a 9x13 baking dish and add broccoli and onions. Pour egg mixture on top. Make sure everything is evenly spread out.

Bake in the oven for 30 minutes, or until the center of the frittata is firm and no longer jiggles or is liquidy.

When frittata is cooked all the way through, remove from oven and sprinkle remaining cheddar cheese on top.

Return to oven until the cheese is melty and bubbling. Approximately 2-3 minutes.

Cut into 6 squares and enjoy!