I’m going to take this opportunity to get two things out of the way. 1: Blini do not and should not contain potatoes. 2: The singular form of the word in question is blin. Blini is the plural form. There is no such thing as blinis.
Ingredients
2 teaspoons active dry yeast
1 cup water, warmed to room temperature
2 teaspoons sugar
1/2 cup all-purpose flour
1 1/4 cups heavy cream
1 1/4 cups whole milk (to make large, slightly thinner blini, omit heavy cream and increase to 3 1/4 cups milk)
1/4 cup melted butter
2 1/3 cups all-purpose flour
2 large egg yolks (you'll use the whites later)
2 tablespoons granulated sugar
2 teaspoons kosher salt
2 large egg whites
Butter for frying
Instructions
The day before you’re going to cook, take a large container (large enough to hold the full batter, and then some), and whisk together the sponge ingredients. Let the mixture sit out at room temperature until doubled, about an hour.
When the sponge has doubled, whisk in all of the remaining batter ingredients. Cover the container, and refrigerate overnight. BE FOREWARNED: this will expand. Much, much more than you might think. Contain accordingly, or scrub the batter off your refrigerator shelves the next day (I know from whence I speak).
The next day, take the batter out of the refrigerator, and let it sit out for an hour or two to come to room temperature. Whisk the egg whites to soft peaks, and gently fold them in.
To cook the blini: Grab a well-seasoned pan, and heat it to a medium-high heat. Melt some butter in the pan. For smaller blini, spoon out 2-inch circles (this batter will be thicker than pancake batter, but should spread more readily — you’ll need about a tablespoon). If you want to make things easier, a squeeze bottle is handy. Cook until bubbles form and pop, and the top dries out, while the bottom cooks to a nice golden (just a few minutes). Flip, and cook the other side. Add more butter and adjust the heat as necessary. Unlike pancakes, which are best hot from the griddle, blini are actually better if they set for a few minutes — hold at room temperature for up to an hour or so.
For larger blini, ladle out 1/4 cup batter, and spread it out to form a 6-inch circle. You want it spread fairly thin so as to be pliable (it’ll puff up a bit). Cook until bubbles form and pop, and the top dries out, while the bottom cooks to a nice golden (just a few minutes). Flip, and cook the other side. Add more butter and adjust the heat as necessary. If the batter is too thick, add more milk as needed. As with small blini, let them set for a few minutes after the come off the heat, and hold at room temperature for up to an hour or so.
Serve blini (of any size) with caviar and butter, smetana and sugar, dipping into machanka, alongside cured fish, for your kid’s after-school snack, etc.