To heat the milk, measure it into a 1-cup heatproof glass measure with pouring spout and microwave it for about 20 seconds. The milk should feel nicely warm to a fingertip. Not hot, or you’ll kill the yeast! Sprinkle in the yeast and sugar, give a quick stir, and let stand until the liquid rises and is bubbly, about 10 minutes.
Put the flour and salt into the large bowl of a stand mixer and stir to combine. Attach the flat beater. If using cold butter, add the pieces and mix on low speed for about 3 minutes until the butter is in pea-sized bits. If using frozen shredded butter, just mix it in on low speed for about 1 minute.
Add the 5 ounces of cheese, the eggs, softened yeast, and 1/2 cup sour cream. Mix on low speed with the flat beater until the dough masses on the blade. If the dough seems dry, add a bit more sour cream. Beat on medium speed 1 minute. The dough should be nice and smooth and non-sticky.
If making the dough by hand, stir everything together with a wooden spoon until the dough gathers into a coherent mass. Add more sour cream if the dough seems too dry.
Turn the dough out onto a lightly floured surface. If you’ve made it by hand, knead briefly to make sure it is nice and smooth and non-sticky. If made with the mixer, just coat it lightly with the flour.
Line a large baking sheet (17 x 12 inches) with cooking parchment. Adjust an oven rack to the lower third position but do not turn the oven on. NOTE: This is what I do according to Marika's directions. If your oven takes a long time to heat up, preheat the oven to 400 degrees before baking the biscuits, and check for doneness 15 to 20 minutes from the time you put the biscuits in the oven.
Roll the dough 1/2-inch-thick (no thinner!) on the lightly floured surface. An 11- to 12-inch diameter circle will give you the right thickness. Make a shallow cross-hatched pattern, about 1/2-inch, with a sharp knife all over the dough surface.
For the topping, combine the egg yolk and water in a small bowl, and brush all over the rolled dough. Sprinkle the cheese on top and press it very gently to stick to the yolk.
With a floured cutter, stamp out rounds with a 1 1/2- to 1 3/4-inch diameter. If the biscuits stick to the cutter, nudge them loose with the tip of a paring knife. If you wish, cup the palms of your hands around each biscuit to smooth the sides. Gather the leftover dough and reshape into a ball. Roll out and cut our circles as before. I don’t bother glazing them with egg yolk or topping with cheese because these ingredients are mixed into the dough during reshaping of the scraps.
Arrange the biscuits in rows about 1/2-inch apart on the baking sheet. Put the pan in the oven and turn the oven on to 400 degrees. Bake about 25 minutes, until the pogácsa are nicely browned on their tops and bottoms. Cool completely and store airtight.
Pogácsa may also be frozen for up to 1 month. Thaw and reheat in a moderate oven for 5 to 8 minutes to refresh them.