Clean the shrimp and place them in a bowl. Add Shaoxing wine and 1/2 tsp black pepper sea salt. Mix well and let marinate for 10-15 minutes to allow the shrimp to fully absorb the seasoning and remove any fishy odor.

Cut the mixed-color tomatoes in half.

Break the broccoli into small florets, soak in salted water for 5-10 minutes, then rinse thoroughly.

Remove the stems of the button mushrooms and slice them thinly.

Dice the onion.

Crack the 3 eggs into a bowl, add 1/2 tsp black pepper sea salt, and whisk well with chopsticks until the egg mixture is fully combined with the seasoning.

Heat a pan and add the appropriate amount of butter (or olive oil). Once the butter has melted, add the diced onion and sauté on low heat to release the fragrance.

Add the marinated shrimp and cook until both sides change color. Remove the shrimp from the pan and set aside.

In the same pan, add the chopped tomatoes, broccoli florets, and sliced mushrooms. Stir-fry on medium heat for about 1 minute until the vegetables soften slightly and release their aroma. Stir occasionally to ensure even cooking.

Return the cooked shrimp to the pan, mixing them with the vegetables. Then, pour the egg mixture evenly over the shrimp and vegetables, ensuring the egg covers all ingredients.

Cover the pan with a lid (or use aluminum foil to cover the pan if no lid is available). Cook on low heat for 3-5 minutes until the egg mixture sets and is fully cooked.

Once the egg is fully set and cooked through, turn off the heat. Carefully transfer the frittata from the pan to a plate. Slice into small portions and serve.