Whisk yogurt, milk, vinegar, oil and vanilla until smooth and creamy
Mix in oat flour, baking powder and sweetener
Let the batter rest for 5 minutes so oats absorb liquid
Split batter into 2 bowls and mix cocoa into one to make chocolate batter
Heat paniyaram pan on low flame and lightly grease each mould
Add small spoonful of vanilla batter first, then add spoonful of chocolate batter on top
Alternate vanilla and chocolate batter and fill each cavity approximately ¾ full
Swirl gently with a toothpick for marble effect
Cook 2-3 minutes on low, flip, cover and cook 2 minutes, flip again and cook 1 minute
Serve warm, optionally drizzle with dark chocolate
