Begin by pressing the firm tofu to remove excess moisture, which enhances its crispiness. Cut the tofu into bite-sized cubes, approximately 1-inch in size, and set aside.

In a large non-stick pan or wok, add 2 tablespoons of vegetable oil and heat it over medium-high heat until shimmering.

Carefully add the cubed tofu to the hot oil. Sauté without stirring for about 2-3 minutes until the bottom is golden brown. Toss occasionally for another 2-3 minutes until evenly browned.

In the same pan, add an additional dash of oil if needed. Stir in 3 cloves of minced garlic and 1 tablespoon of freshly grated ginger. Sauté for about 30 seconds until fragrant.

Add the sliced mixed mushrooms, broccoli florets, and bell peppers to the pan. Stir-fry for 5-7 minutes until they become tender-crisp.

Return the golden-brown tofu back into the pan. Pour in 3 tablespoons of soy sauce, a sprinkle of black pepper, and 1/2 cup of vegetable broth. Stir gently to coat.

Gradually add the cornstarch slurry made with 1 tablespoon of cornstarch and 2 tablespoons of water, cooking while stirring for 2-3 minutes until the sauce thickens.

Remove from heat and serve piping hot over rice or noodles, garnished with sesame seeds or green onions if desired.