Start by washing the broccolini thoroughly under cold water. Trim the ends and cut the broccolini into bite-sized pieces. Set aside.

Bring a pot of salted water to a boil. Add the broccolini and cook for about 2-3 minutes until bright green and tender-crisp. Immediately transfer the broccolini to a bowl of ice water to stop the cooking process. Drain and set aside.

In a large skillet, melt 2 tablespoons of the unsalted butter over medium heat. Add the cauliflower gnocchi and cook for about 5-7 minutes, stirring occasionally, until the gnocchi is golden brown and crispy on the outside. Remove the gnocchi from the skillet and set aside.

In the same skillet, add the avocado oil and heat over medium heat. Add the chopped spring onions and minced garlic, and sauté for about 2 minutes until fragrant.

Add the cubed portobello mushroom to the skillet and cook for another 3-4 minutes until the mushrooms are tender and slightly browned.

Reduce the heat to low and add the blanched broccolini and cooked gnocchi to the skillet with the vegetables. Stir gently to combine.

Add the remaining 2 tablespoons of unsalted butter and mustard to the skillet, stirring until the butter is melted and the mustard is well incorporated.

Season with ground pepper to taste.

Sprinkle the grated Parmesan cheese over the gnocchi and vegetables. Stir gently until the cheese is melted and everything is well combined.

Serve the dish hot, garnished with additional Parmesan cheese if desired.