Savory Vegan Croissant Casserole

Name: Savory Vegan Croissant Casserole
Ingredients: 5 vegan frozen croissants for baking (e.g., by MOIN Bio Backwaren; 2 tbsp flaxseeds; 2 tbsp light sesame seeds; 2 tbsp sunflower seeds; oat cream for brushing; 2 onions; 4 cloves of garlic; 250 g (9 oz) brown mushrooms; 50 g (2 oz) fresh spinach leaves; 150 g (5.5 oz) cherry tomatoes; 200 g (7 oz) smoked tofu; 1 tbsp soy sauce; 150 g (5.5 oz) vegan feta; Salt; Pepper; neutral vegetable oil for frying; chives for serving; 200 g (7 oz) silken tofu; 100 g (0.5 cups) vegan yogurt; 2 tbsp chickpea flour; 5 tbsp nutritional yeast; 1 tsp kala namak; 2 tsp mustard; nutmeg; pepper