Preheat your oven to 400ºF (200ºC).

Combine soy sauce, ketchup, oil, salt, garlic powder, and freshly ground black pepper in a large bowl. Toss in the cauliflower florets until they're evenly coated.

Coat the cauliflower with cornstarch, ensuring each floret is fully covered. Spread them on a parchment-lined baking sheet.

Bake in the preheated oven for 24-28 minutes until golden brown and crispy.

Sauté garlic, ginger, and dried red chilies in a skillet over medium-high heat until fragrant.

Add the chopped onion and celery, cooking until translucent.

Stir in the soy sauce, maple syrup, black pepper, and white pepper to create the sauce.

Mix cornstarch with water in a separate bowl, then pour into the skillet. Stir until thickened.

Toss the baked cauliflower in the skillet with the sauce.

Garnish with chopped green onion and sesame seeds before serving.