Prep vegetables. Wash and slice the yellow squash. Place the squash and chopped onion in a microwave-safe bowl.
Add water. Pour in just enough water to cover the bottom of the bowl, about ½ to 1 inch deep.
Microwave. Cover tightly with microwave-safe plastic wrap and microwave for 3 to 4 minutes, or until the squash is tender. Add additional 30 second to 1 minute increments if softer squash is desired.
Season. Carefully drain off excess water. Sprinkle in the salt, black pepper, garlic powder, and Italian seasoning. Toss gently to coat.
Serve. Serve warm.
Notes
Water amount. Water is added by sight, not strict measurement. Use just enough to lightly steam the vegetables.
Microwave timing. Cooking time varies by microwave strength. Squash should appear slightly translucent when done.
Safety. Use only microwave-safe bowls and plastic wrap, and vent carefully when removing the cover.