Pre-heat oven to 350 degrees
Finely dice 1 red onion, halve 1 pint cherry tomatoes, and roughly chop pepperoni & mozzarella. Set aside.
In a large sauté pan, heat 1T olive oil on high, add diced onion. Cook ~5-10 min.
Season w/ ½t salt & 1T pizza seasoning. Add halved tomatoes & 1 bag baby spinach. Cook 5-10 more minutes, stirring and adding oil if needed. Set aside to cool.
Whisk 8 eggs in large bowl, season w/ S&P. Stir in cooked veggies & chopped pepperoni & cheese. Pour into an oiled pie pan.Bake at 350 F for 45-50 minutes or cooked through and no longer jiggly in the center (cover w/ foil after top browns). Cool.