Cook broccoli in boiling water for eight minutes. Transfer immediately to a bowl of ice water and let sit for a couple of minutes. This retains the bright green color. Strain.
Roast the peppers under the broiler. Peel charred skin and drain. Cut into thin strips.
Begin the process of cleaning and cooking the broccoli (or cauliflower) a day ahead, and store in an airtight container in the fridge.
Combine all dough ingredients and knead until the dough takes shape.
Roll out and place in a large baking pan, letting the edges go up the sides.
Bake for 15–20 minutes at 350 degrees Fahrenheit (180 degrees Celsius) until the crust just starts to get brown, no longer. Remove from oven.
Place half of the cheese filling on top of the baked crust.
Separate the broccoli into florets and place evenly all over crust. Place roasted pepper slices evenly all around.
Sprinkle remaining cheese filling on top of the vegetables.
Place all ingredients for the crème royale into a bowl and whisk until frothy. Pour over everything and bake for another half hour until golden.
Cool until set.