Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper.
In a bowl, mix flour and water into a smooth batter. Dip cauliflower florets in the batter, shake off excess, then coat with breadcrumbs and sesame seeds.
Place coated florets on the baking sheet and bake for 25-30 minutes until crispy and golden.
Meanwhile, prepare the sauce by combining soy sauce, honey, rice vinegar, ginger, and garlic in a saucepan over medium heat.
Stir in the cornstarch mixture and cook until the sauce thickens. Remove from heat.
Toss the baked cauliflower in the sticky sesame sauce until well-coated.
Serve warm, garnished with sliced green onions.