Mexican corn croquettes

Name: Mexican corn croquettes
Prep time: 45 min
Total time: 45 min
Cuisine: American, Mexican, Latin American
Ingredients: 2 corn cobs; salted water; 1 tbsp olive oil; 1 onion; 2 garlic cloves; 1 tsp ground coriander seeds; 1 tsp dried thyme; 1 tsp chilli flakes (e.g. Fine Food Chile Chipotle); 3 ½ dl water; 1 tsp salt; 100 g medium-fine polenta; 50 g Maizena cornflour; 30 g butter; 1 fresh egg yolk; 60 g panko breadcrumbs; oil , for deep-frying; 100 g sour single cream; 1 tbsp mayonnaise; 1 lime; ¼ tsp garlic powder; 2 pinches salt; ¼ bunch coriander