In large bowl, whisk eggs and milk together.
Put ½ cup of egg milk mixture in separate bowl or jar and add baking powder and flour. Mix vigorously to combine so that there are no clumps of dry ingredients. You can also pulse in a small blender to throughly combine (I use my bullet blender).
Re-add the egg, milk, flour, baking powder mixture back into the main egg/milk mixture.
Chop onion, tomato, mushroom, olive and artichoke mixture and add to milk/egg mix.
Add cheese to wet mixture and thoroughly combine.
Grease 9x12 baking dish and pour mixture into dish.
Place sliced rounds of pepper on top.
Preheat oven to 375 and bake for 40-45 minutes. Check with knife in middle to be sure cooked through (should not come out wet).