Place the eggs, flour, oats, oat drink and cinnamon into a food processor. Blend until you have a smooth, thick batter. Add the baking powder and pulse briefly to combine.
Let the batter rest for 10 minutes to allow the oats to soften and the mixture to thicken slightly.
Meanwhile, prepare the cherry topping. Drain the liquid from the sour cherries into a small saucepan. Add a little muscovado sugar to taste and a pinch of cinnamon. Simmer gently until reduced to a light syrup. Return the cherries to the pan, stir to coat and keep warm.
In a bowl, mix the ricotta with the maple syrup, lemon juice and lemon zest until smooth and creamy. Set aside.
Lightly oil a non-stick pancake pan and heat over medium heat. Spoon dollops of batter into the pan, allowing them to spread into small circles.
Cook until the surface is no longer runny and small bubbles appear, then flip and cook for another minute or so until golden on both sides. Transfer to a plate and repeat with the remaining batter.
To serve, stack about four pancakes on each plate. Add a generous spoonful of lemon ricotta on top, then spoon over the warm sour cherries, allowing the syrup to drizzle down the sides.
Serve immediately while warm.