Preheat the oven to 350 degree F. Lightly grease a 3-quart (9 by 13-inch) baking dish with 1 tablespoon of the butter and set aside.
In a medium skillet, melt 2 teaspoons of the butter over medium-high heat. Add the onions, green and red bell peppers, 1/4 teaspoon of the salt, and 1/8 teaspoon of the pepper and cook, stirring, until soft, 3 minutes. Add the garlic and cook, stirring, until fragrant, 30 seconds. Add the parsley, stir, and remove from the heat. Let cool.
In a medium skillet, melt the remaining 1 teaspoon butter over medium-high heat. Add the Canadian bacon and cook, stirring, for 3 minutes. Remove with a slotted spoon and drain on paper towels. Add the sausage to the skillet and cook, stirring, until lightly browned, 5 to 6 minutes. Drain on paper towels and let cool.
In a large bowl, beat the eggs. Add the milk, cream, 1 teaspoon of the Essence, remaining 1/2 teaspoon salt, and remaining 1/8 teaspoon pepper and whisk to combine. Add the bread cubes and let sit for 5 minutes. Add the cooked Canadian bacon and sausage, the onion mixture, and the Gouda cheese and stir to incorporate the ingredients. Pour into the prepared dish, cover with aluminum foil, and bake until almost completely set, 50 to 55 minutes.
(Alternatively, the bread pudding can be assembled up to this point, covered, and refrigerated 8 hours or overnight, and then baked. Let sit at room temperature while preheating the oven, before baking. ).
In a small bowl, combine the bread crumbs, Parmesan, melted butter, and remaining 1/2 teaspoon Essence. Uncover the pudding and sprinkle the bread crumb mixture evenly over the top. Return to the oven, increase the heat to 375 degrees F and bake until the pudding is completely set in the center, puffed, and golden brown on top, about 20 minutes.
Let sit for 15 minutes before serving.