1/2 c grapeseed oil
1/2 c butter
5 egg yolks
2 tbsp vinegar or lemon juice
pinch of salt
fresh ground pepper
1. Melt butter and combine with oil.
2. In a blender, combine yolks, vinegar, salt and pepper. Pulse a few times then blend on a medium speed for 30 seconds.
3. Make sure oil/butter mixture is hot then with the blender running, slowly drizzle it into the yolk mixture.
4. Serve immediately. (If you must reheat it, do so carefully as it is easy to break the emulsion or cook the eggs. Better over the stove than in the microwave. Extra can get stored in a mason jar in the fridge.)
This makes about 1.5 cups.
Try it over roasted asparagus or steak. You can also make this using only oil if dairy isn't your thing.