2 medium size sundried tomato, drained and finely chopped (optional)
For the polenta:
5 cups low sodium chicken broth, or vegetable broth
1 cup instant polenta
1/2 cup parmesan cheese
1/2 teaspoon kosher salt, more to taste
Adjust oven rack to middle position and preheat oven to 450°F. Drizzle a sheet pan with 1 tablespoons of olive oil. Set aside.
For the panko crumbs, melt butter till bubbly in a small sauté pan. Add pine nuts and stir continuously for about 1 minute, till nuts and butter turn a light, golden brown. Remove pan from heat, then remove pine nuts with a slotted spoon to a plate lined with a paper towel. Add garlic to butter in pan and return to medium low heat. Cook for 15-30 seconds or until fragrant. Add panko crumbs to the pan and stir to combine. Cook, stirring continuously for 1 minute to crisp crumbs. Remove from heat, Add lemon zest, parsley and finely chopped sundried tomato.
Wash and remove any outer leaves from the cauliflower, but leave the stem intact. Place head stalk side down on a cutting board. Using a large chef's knife, slice cauliflower into 3/4" wedges. Arrange cauliflower slices and any pieces in a single layer on prepared baking sheet, placing any stray pieces in the center of the pan. Drizzle with remaining oil and season with salt and pepper. Cauliflower shrinks during the roasting process.
Roast until underside is deep golden brown, 15–25 minutes. Turn cauliflower over, season with salt and pepper, and continue to roast until other side is deep golden brown and crisp, 15–20 minutes longer.
While the cauliflower steaks are roasting, make the polenta. Bring broth to a boil in a medium large pot.While the broth boils, slowly add polenta, stirring or whisking continuously to prevent lumps. Once all polenta has been incorporated, lower eat to a gentle simmer and cook, uncovered for 6-8 minutes. Add parmesan and salt and stir to incorporate. Polenta should be thick but spoonable. If it gets too thick, you can add a bit more chicken broth, to thin.
To serve, spoon polenta into four shallow bowls. Arrange cauliflower steaks on top and sprinkle with panko mixture and pine nuts. Garnish with parsley and lemon slices.