Set aside 1/3 cup of peas.
Add the remaining peas to a blender with the water and egg; purée until smooth.
Pour the mixture into a medium bowl and stir in the flour, salt, and baking powder and gradually mix with a fork or whisk.
Stir in the reserved 1/3 cup peas.
Let the batter rest for 10 minutes while you clean up.
Place about 2 tablespoons of oil in a sauté pan, warm over medium heat until shimmering, and drop 1 tablespoon of batter in the pan. Gently cook for about 3 minutes, until you see bubbles forming around the edges. Flip and cook on the second side until very lightly browned. Continue until all the batter is gone.
Serve warm with butter or plain yogurt.