To begin, dissolve two packages of dry yeast in warm water until the mixture becomes foamy. Next, scald the milk and remove it from the heat. Mix in sugar, salt, and butter until well-blended, and allow it to cool until it reaches a lukewarm temperature.
Add the eggs one at a time, ensuring that each egg is thoroughly mixed in. Incorporate the yeast mixture, vanilla, cinnamon, nutmeg, and raisins. Gradually add flour, a cup or two at a time, mixing well for about five minutes. The resulting dough will be sticky and wet.
Cover the dough and allow it to rise in a warm location until it doubles in size. Meanwhile, prepare the streusel topping by mixing the ingredients until they are crumbly.
Once the dough has risen, punch it down. grease either two 9x5" loaf pans or three smaller ones. Divide the dough between the pans, patting it down to even it out. Sprinkle the streusel topping over the loaves and let them rise in the pans until the dough reaches the top of the pans.
Bake the loaves at 350 degrees Fahrenheit for 35 minutes or until they are golden brown. To avoid sugar spilling over and causing a mess in the oven, place the pans on a baking sheet. Remove the pans from the oven and take the loaves out of the pans, placing them on a rack to cool.