Juicy Kangaroo Burger with Vegemite

Name: Juicy Kangaroo Burger with Vegemite
Prep time: 10 min
Cook time: 15 min
Total time: 25 min
Cuisine: Australian
Ingredients: 1.1 lb kangaroo mince; 1/2 medium onion (finely diced); 1 teaspoon fresh rosemary or thyme (finely chopped, or 1/2 teaspoon dried); 1/2 medium lemon (zest only, finely grated — or use lime); 2-3 cloves garlic (minced); 1 pinch salt (to taste); 1 pinch ground black pepper (to taste); 1/2 teaspoon smoked paprika (optional); 2 tablespoons olive oil (30ml); 2-3 tablespoons ground flaxseed or breadcrumbs (as needed for firmness); 1/2 tablespoon Vegemite (or to taste); 6 whole burger buns (toasted)