Cook the polenta - Whisk together water, butter, polenta, salt, garlic powder, and pepper in a medium pot over high heat. Bring to a boil, then reduce to low. Loosely cover with lid to avoid splattering and stir occasionally for 20 minutes, until thick.
Prep the dish and chill the polenta - Line the pan with parchment paper. Stir grated cheese into the polenta, then pour into the prepared pan. Smooth the top, cover and chill for 2 hours or overnight to let it set up.
Preheat the oven and prep the polenta croutons - Preheat the oven to 425°F. Unmold the polenta and slice into 1-inch squares. In a large bowl, gently toss chilled polenta cubes with olive oil to coat. Add bread crumbs and toss again until evenly coated. Spread the polenta cubes out on a foil-lined baking sheet, and bake for 15 minutes.
Serve - Allow to coil slightly. Serve warm or room temperature atop your favorite salad.