In a food processor, combine the sugar, yolks, vinegar or lemon juice, mustard, salt, garlic powder and onion powder. Give that a pulse so everything is combined. Then while the processor is running slowly, drizzle in the oil. Last, add the poppy seeds and give that just one more pulse to combine.
Store in an airtight container in the refrigerator for up to 3-4 days. If the poppy seeds settle, just give the dressing a good shake before using.
*If you're not feeling the egg yolks, you can substitute 2 tablespoons mayo (even a vegan mayo if you prefer). If you do, you can just combine all the ingredients in a jar, add a lid, and shake until well combined. Without the yolks, there isn't as much need to slowly drizzle in the oil.