Tortellini Marinara and Zucchini Bake

INGREDIENTS

1 tsp

olive oil ((extra virgin))

zucchini ((uncooked, small))

1/2

onion ((chopped))

1 1/2 tsp

minced garlic

2 cups

marinara sauce (, divided (store bought))

4 cups

fresh baby spinach

1/4 tsp

salt

1/4 tsp

black pepper

1/4 tsp

crushed red pepper flakes

3 cups

cheese tortellini ((without sauce-cooked and drained))

1/2 cup

part-skim mozzarella cheese (, shredded)

1/4 cup

Parmesan cheese ((+ additional for garnish, if desired))