Step 1

In the bottom of a double boiler (medium saucepan) add 1” of water and turn the heat to medium.

Step 2

In the top bowl of the double boiler (glass bowl that can rest slightly in the saucepan but not touch the water) add the mustard powder, sugar, salt, flour and water. Whisk to combine.

Step 3

In a small bowl whisk together the egg yolks and vinegar. Pour that into the water mixture and whisk.

Step 4

Place the bowl on top of the double boiler and keep whisking until the mixture thickens and can coat the back of a spoon. 8-10 minutes.

Step 5

Remove the bowl from the heat and whisk in the butter. Once the butter is incorporated, add in the cream, whisking to blend.

Step 6

Add in the celery seed and pepper. Taste for salt.

Step 7

Pour into a glass container and once, cool, cover and store in the fridge for up to one week.