Step 1Combine the cornmeal, sugar and salt in a bowl and very slowly whisk in the boiling water to make a stiff paste. Let stand 10 minutes to cool.
Step 2Stir in the eggs, one at a time, then the milk. Sift the flour over the egg mixture. Add the butter and stir until smooth. The texture should be somewhere between thick whipping cream and thin yogurt; if necessary, add a little more milk to thin it. Stir in the corn and pepper. Cover and refrigerate 30 minutes. Heat oven to 250 degrees.
Step 3Heat a nonstick pan over medium-high heat. Add a little butter and swirl it around the base of the pan to grease it. Slowly pour in 2 scant tablespoons batter and cook until lightly browned and slightly crisp on one side, 2 to 3 minutes. You can cook 5 or 6 blini at a time.
Step 4When lightly browned on one side, turn and cook 1 to 2 minutes on the other side. Transfer the cooked blini to a baking sheet lined with aluminum foil and keep warm in the oven. Repeat using the rest of the batter, adding more butter if necessary.
Step 5Transfer blini to a warm plate and top with about one-half teaspoon of crema fresca and a cilantro leaf. Serve immediately.