Breville Test Kitchen
Root Vegetable and Whole Grain Mustard Gratin
This recipe is tuned in for your Paradice 9. Once you download the Breville+ app, your culinary co-pilot will give you step-by-step guidance through your cook by color journey.

the Paradice™ 9
+4 more appliances
2 hrs total time
20 mins active time
Easy
Serves 8-10
Ingredients
Measurements:
5 oz Comte cheese
3½ oz parmesan cheese
4 cloves garlicpeeled
1 red onionpeeled and halved
1⅓ lb celery rootpeeled and cut into large pieces
1⅓ lb butternut squashpeeled and cut into large pieces
1⅓ lb potatoespeeled
1 oz unsalted butter
2 tbsp yellow mustard seeds
2 cups (16 fl oz) creamdivided
3 tbsp thyme leaves
2 tbsp whole grain mustard
2 tsp kosher salt
Finely ground white pepperto season
Instructions
- 1
Assemble the processor with the grey spindle and yellow reversible shredder, with the fine side up in the bowl and shred both cheeses. Remove and set aside.
- 2
Carefully assemble the clean processor bowl with the grey spindle and green S-blade™. Add the garlic and process until finely chopped, scraping down the side occasionally. Carefully remove the S-blade™ leaving the garlic in the bowl.
- 3
Assemble the processor with the grey spindle and orange adjustable slicer set on 2 in the bowl and slice the onion. Remove and set aside.
- 4
With the process still set up with the slicer set on 2, slice the celery root and transfer to a large mixing bowl. Slice the squash and then the potatoes and transfer to the mixing bowl. Mix the vegetables to distribute evenly.
- 5
Melt the butter in a large frying pan over medium-high heat. Add the garlic and onion and mustard seeds and saute for 4 minutes, or until softened. Add 1½ cups (12 fl oz) cream and thyme and bring to a boil. Reduce the heat and simmer for 2 minutes to infuse. Add the whole grain mustard, salt and pepper and stir to combine.
- 6
To preheat the oven, insert the wire rack into position 6. Set the oven to Bake, Convection, 325°F, Rotate Remind, for 1 hour 15 minutes and press Start. Meanwhile, continue to the next step.
Tip: Recipe as been optimized for the Joule Oven Air Fryer Pro and the Smart Oven Air Fryer Pro. - 7
Pour the hot cream over the vegetables. Add the remaining ½ cup (4 fl oz) cream and mix to coat. Place half the vegetables in a 11-inch x 9-inch baking dish and flatten. Sprinkle over half the cheese and repeat with the remaining vegetables and cheese. Cover with foil.
- 8
Once preheated, place in the oven and bake for 1 hour 15 minutes. When the Rotate Remind signals, remove the foil and continue baking until golden brown and the vegetables are tender when tested with the tip of a knife.
- 9
Remove from the oven and allow to stand for 10 minutes before serving. Serve sprinkled with finely chopped parsley, if desired.