Preheat your oven to 400F and line a large baking sheet with parchment paper.
Alternatively, you can use 2 medium baking sheets. Slice the zucchini 1 inch thick, and using a melon baller, scoop a bit from the inside, to create a small cup that will hold in the sauce.
Arrange the zucchini on a prepared baking sheet and top with marinara sauce, mozzarella, and pepperoni slices.
Bake in the preheated oven for 8-10 minutes, or until the cheese melted and bubbly.
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Notes
If you don't have marinara sauce, low-carb pizza sauce or tomato sauce works great too.
Mozzarella works great on these Zucchini Pizza Bites, but they can be made with any cheese.
To make larger rounds, slice zucchini diagonally.
Strands of pre-shredded mozzarella can be too long and messy, finely shred your own or roughly chop bagged shredded mozzarella to make sprinkling easier.
You can use a grill pan or a nonstick skillet.
Finely dice some red or yellow bell pepper and sprinkle it on top for more veggie goodness!
Feel free to top with your favorite pizza toppings, chopped up!