Freezer-friendly Brown Rice Muffins

• 250 g cooked brown rice and quinoa (microwavable)
• 1 zucchini, skin on, grated
• 150 g sweet potato, skin on, grated
• 200 g tin corn kernels, drained
• 3 eggs
• 2 tsp lemon herb and garlic seasoning
• 1 tsp extra virgin olive oil
• 100 g feta cheese
• 1 cup parmesan cheese