Spinach & Cheddar Quesadilla with Biltong

Name: Spinach & Cheddar Quesadilla with Biltong
Ingredients: 250 ml grated cheddar; a squeeze of lemon juice; salt and freshly ground pepper; extra grated cheddar cheese; sliced biltong; spinach, roughly chopped; 4 tortillas; 30 ml pesto of choice; 1 onion, sliced; 15 ml olive oil; 2 garlic cloves, finely chopped; 15 ml olive oil; 250 g mushrooms, sliced