Vegan beetroot burger with cheese sauce

Name: Vegan beetroot burger with cheese sauce
Ingredients: 500 g beetroot; 1 clove garlic; 2 sprigs thyme; 15 mL olive oil; 200 g Chestnut Mushroom, finely diced; 1 onion finely diced; 100 mL vegetable oil; 2 cloves black garlic; 1/2 tsp. garlic powder; 1/2 tsp. onion powder; 1/2 Dijon mustard; 125 g cooked beluga lentils; 1 1/2 tsp. salt; Grind of pepper; 35 g roasted pumpkin seeds; 120 g oats; 6 brioche buns; 2 little gem lettuce; 2 plum tomatoes; 340 g silken tofu; 40 g nutritional yeast; 2 tsp. onion powder; 2 tsp. garlic powder; 3 Dijon mustard; 2 tsp. white wine vinegar; 1 tsp. salt; 1/2 tsp. turmeric; 1/2 tsp. smoked paprika