Caramel Latte Crumble Mug Cake

Ingredients

• 4 tbsp all-purpose flour
• 2 tbsp sugar
• 1/4 tsp baking powder
• 1 pinch salt
• 2 tbsp strong brewed coffee
• 1 tbsp milk
• 1 tbsp oil
• 1/4 tsp vanilla extract
• 1 tsp caramel sauce
• 1 tbsp all-purpose flour
• 1 tbsp brown sugar
• 1/2 tbsp cold butter