Step 1Preheat the oven to 190 °C/ 375 °F (fan assisted) 210 °C/ 410 °F. Cop the celeriac into about about 2 cm/ 0.8 inch cubes. Cut the celeriac into small florets. Peel and finely chop the garlic.
Step 2Add the chopped celeriac, cauliflower and garlic cloves to a baking tray. Add the herbs and butter or olive oil, season with salt and pepper and toss well.