• Combine the milk, water, eggs, flour, salt and sugar in a bowl (or blender)
• Blend on medium speed for 15 seconds, until the batter is smooth and lump-free.
• Scrape down the sides of the bowl and pour in 3 tablespoons of melted butter.
• Blend it again for a second just to incorporate.
• Refrigerate the batter for 1 hour (or overnight)  to let it rest. If the crepes are made immediately, they have a tendency to be rubbery; when you let the batter rest, the crepes have a better texture and a softer bite.

CHEESE FILLING:

• In a food processor, combine the ricotta (or cottage) cheese, cream cheese, confectioners' sugar, lemon zest, and egg and blend until smooth. Chill the filling to firm it up a bit so it doesn't squirt out of the blintzes.
• Put an 8-inch crepe pan or nonstick skillet over medium heat and brush with a little melted butter for added assurance.

SAUCE (optional):

• Combine the strawberries, sugar, water, cornstarch, and zest in a small pot over medium heat. Bring to a simmer and stir gently until the berries release their natural juices. The consistency should remain a bit chunky, it will thicken up when it cools down.
• CREPES:
• Pour 1/4 cup of batter into the pan and swirl it around so it covers the bottom evenly; pour back any excess.
• Cook for 30 to 45 seconds, until the crepe batter sets.
• Lightly bang the edge of the pan with a wooden spoon to loosen the crepe; then flip it and cook another 30 seconds. The art of flipping a crepe in the air takes practice, so make sure no one is looking when you get the first one going. If this intimidates you, use a heatproof rubber spatula to loosen and flip the crepe. The crepes should be pliable, not crisp, and lightly brown.
• Slide them onto a platter and continue making the crepes until all the batter is used.
• Cover the stack of crepes with a towel to keep them from drying out.

ASSEMBLY:

• Preheat the oven to 400°F.
• Forming the blintzes is kind of like making burritos. Spoon 1/4 cup of the cheese filling along the lower third of the crepe.
• Fold the bottom edge away from you to just cover the filling; then fold the 2 sides in to the center.
• Roll the crepe away from you a couple of times to make a package, ending with the seam side down.
• Put an ovenproof skillet over medium heat. Brush with melted butter.
• Set the blintzes into the pan, and brush lightly with melted butter-- unless you plan to "fry" the blintzes on the stove with butter (see below).

Optional before baking the blintzes:

• Fold in both sides, then roll up crepe into a small filled rectangle, ending with the seam on the bottom, creating a blintz. Melt about 1 tablespoon butter in skillet over medium heat. Cook the blintzes until golden brown on both sides, turning gently, about 2 minutes.
• Transfer the pan to the oven and bake for 10 minutes so the egg in the filling cooks slightly and the cheese sets.

To serve:

• Using a spatula, transfer the blintzes to serving plates. Top with sour cream and fruit or preserves.