Mix 2 cups of flour, 1/2 cup of sugar, yeast, and salt. Add 1.5 cups of hot water (but not boiling). Beat this and then add eggs, mixing. Add the other 3 cups of flour.
Knead until smooth and satiny, about 8 to 10 minutes. Form into a ball.
Lightly grease a large bowl (at least twice as large as your ball of dough). Put the dough round side down in the greased bowl, then turn over so that the greased side is up. Cover with a slightly damp towel. Put in a warm place (or as warm as you have in the winter, but not a lit oven). Let it rise until doubled, about 75 minutes. You don't want to leave the dough too long, however. Dough can actually over-rise.
Punch down the dough. Reshape into a ball. Recover bowl. Let rise till double. It should take less time this time around, but it varies -- maybe 45 - 60 minutes. All of these rises can take longer if your house is cold.
If using a prune filling, simmer them with some water until soft; mash thoroughly. Let cool.
If desiring an apricot filling but not having access to canned Solo filling, you can make it out of dried apricots. Snip 3/4 cups of dried apricots into small pieces. Simmer,covered, with 1-1/2 cups water for 10 minutes. Simmer uncovered for 10 minutes more. Stir in 2 tablespoons of sugar. Let cool before using.
Pinch off balls of dough about 1.5 inches in diameter. Pat out into a circle. Put a spoonful of filling inside. Fold over and seal. Put in pan. Parchment-lined cookie sheets work well. The recipe doesn't say it, but I'd leave some room between them because they'll grow during the next rise -- yep, let rise again. This rise should be 45 - 60 minutes.
Make topping: crumble together 1.25 cups flour, sugar and butter.
Make a groove in the center of each and put on a big pinch of topping. Bake at 350°F until nicely golden brown, about 15-20 minutes.
NOTE: This is how my recipe card reads; however, I swear that I remember her making them the following way. Pinch off the ball of dough. Make an indentation in it. Fill with a spoonful of the filling. Sprinkle topping on it before baking.