Preheat oven to 350°F (180°C). Line muffin tin with greased paper cups.
In large mixing bowl, stir together flour, baking powder, baking soda and salt until combined. Stir in 1 cup (250 mL) Cheddar, bacon, zucchini and green onions. In separate bowl, whisk together eggs and buttermilk; stir into flour mixture along with mixed vegetables just until combined (do not overmix).
Spoon batter into prepared muffin cups; sprinkle remaining cheese over top. Bake in centre of oven for 20 to 25 minutes or until tops are golden and tester inserted into centre comes out clean. Let cool on rack for 10 minutes; serve warm.
• Omit bacon for a vegetarian alternative
• Fresh summer herbs, such as basil, thyme or rosemary, can also be added.