Step 1

Make the roasted garlic: Preheat the oven to 400˚ F. Cut the top 1 inch off the garlic heads and place on a large sheet of foil, cut-sides up. Drizzle with the olive oil and season lightly with salt and pepper. Wrap the foil around the garlic heads and bake until the garlic is browned and soft, about 1 hour. Remove from the oven and unwrap. When cool enough to handle, squeeze the garlic cloves out of their skins. You should have about 1 cup roasted garlic.

Step 2

Bring a large pot of salted water to a boil. Meanwhile, make the glaze: Combine the roasted garlic, olive oil, Dijon mustard, shallot, vegan mayonnaise, 1 teaspoon salt, 2 teaspoons pepper, the sage and rosemary in a blender and puree until smooth. Transfer the glaze to a bowl and stir in the grainy mustard.

Step 3

Working in batches if needed, add the cauliflower to the boiling water and cook until slightly puffed and yellowed, 8 to 10 minutes. Drain and let cool.

Step 4

Preheat the oven to 400˚ F (use the convection setting, if available). Transfer the cauliflower to a rimmed baking sheet. Brush with the sunflower oil and sprinkle with 2 teaspoons each salt and pepper. Bake 10 minutes.

Step 5

Remove the cauliflower from the oven and pour the mustard glaze evenly over each head. Return to the oven and bake until the glaze turns golden brown, 8 to 12 minutes.