In a small saucepan, bring vinegar to a boil.
Remove from heat and whisk in mustard powder; cover and allow to stand 6 hours or overnight.
Whisk in the honey and egg yolks, and replace the pan on low heat, cooking and stirring until mixture is thickened, about 5 minutes.
Remove from heat and cool.
Store mustard refrigerated in airtight container for up to 1 month; pairs well with sandwiches, chicken, ribs, and soft pretzels.
