Preheat oven to 375°F (190°C). Grease a 9x13-inch casserole dish with butter.
1 tablespoon butter
Spread the English muffin cubes on a baking sheet and toast for 10–12 minutes, until lightly golden. Cool for at least 15 minutes.
6 English muffins
Add toasted muffins and Canadian bacon to the buttered dish. Toss gently to combine and spread evenly.
8 slices Canadian bacon
In a large bowl, whisk together eggs, milk, mustard, paprika, garlic powder, salt, and pepper. Pour the custard mixture evenly over the muffins and bacon.
8 large eggs, 2 cups whole milk, 1 tablespoon Dijon mustard, ½ teaspoon paprika, ½ teaspoon garlic powder, ¾ teaspoon salt, ½ teaspoon freshly ground black pepper
Let rest at room temperature for 30 minutes to 1 hour, or cover and refrigerate overnight (up to 24 hours).
Bake uncovered for 35–40 minutes, until the custard is set and the top is golden.
Cool for 10 minutes, then sprinkle with parsley. Serve with hollandaise drizzled on top (about ⅓ cup) and the rest on the side.
Fresh parsley