Begin by peeling your celery root and dicing it up. It doesn’t need to be pretty but it should be regular so everything cooks evenly.
Preheat a pan over medium low heat and add a few tbsp of neutral oil. Once the oil shimmers add the celery root and cook over this low heat for 10-15 minutes, stirring every now and then, until the celery root is tender. Grab a fork and see if it’s easily pierced. Cover with the heavy cream and cook until everything is completely soft, you should be able to grab a piece and smush it in-between your fingers. Around another 5 minutes of cooking. Remove from the heat and reserve.
Place your butter in a small pot over medium low heat and melt. Once it’s melted and begins to foam add the milk powder while whisking. Cook while whisking constantly until the milk solids are a golden brown, do not walk away from this. The milk solids will keep cooking and darken slightly once you pull it off the heat. Aim for a nice peanut butter color.
You shouldn’t have very much liquid in your pan with the celery root but if you do, use a slotted spoon to scoop the celery root into the blender and leave the liquid behind. You can add the liquid as needed to get it to spin. Add the celery root and the butter to a blender with a pinch of salt and blend completely smooth. Taste and adjust your salt.
Green sauce
3/4 cup neutral oil- I use sunflower oil
1/4 cup picked parsley
1/4 cup chives
1/4 cup picked dill
1 tbsp coriander seed
1 clove garlic
1 tsp sherry vinegar
salt to taste
First place your oil in the freezer for around an hour. Getting the oil really cold lets you blend it longer before it gets hot and starts cooking the herbs.
Place the coriander seeds in your blender and pulse a few times to begin breaking them down. Add the garlic, herbs, sherry, oil, and a pinch of salt. Blend completely smooth. Be careful not to blend it too long or eventually the oil will heat up and you’ll lose that bright fresh herby flavor.