Heat oil in a large stock pot over low-medium heat. Add fennel and saute for 10-12 minutes until beginning to caramelize, stirring occasionally. Add leeks and continue to saute for 10 minutes, stirring occasionally.
Add broccoli, kale and Parmesan rinds (if you have them). Cook for about 5 minutes, stirring occasionally, until broccoli starts to turn bright green. Add minced garlic to the pot; season with salt, pepper & red pepper and cook stirring for 2-3 min. Pour in chicken stock to cover and add thyme. Bring to a simmer.
Simmer for at least 30 minutes but up to 1 1/2 hours. Remove thyme branches and Parmesan rinds.
About ten minutes before ready to serve, brown meatballs in about 1/2 tbsp each canola oil and butter for about 5 minutes. Add to soup pot and cook for an additional 6-8 minutes.
Cook pasta according to package instructions, it should take about 5 minutes.
Remove soup from heat and stir in lemon juice. Serve with a couple of spoonfuls of pasta and top with parsley and Parmesan.
*Note: Serves 8 1 1/2 cup entree portions or 12 1 cup appetizer portions.