In a large mixing bowl, stir the eggs, sour cream, milk, oil, agave and extract.
In a separate bowl, whisk together all dry ingredients, including quick rise yeast. Slowly stir into the large mixing bowl, using a paddle attachment on a stand mixer, or mixing by hand with a wooden spoon.
Beat for 2 minutes until all ingredients are integrated well, then stir in the raisins.
Line a baking sheet with parchment paper and set aside.
Scoop batter onto parchment using an ice cream scoop or large spoon. They should form approximately 8 smooth buns (wet a rubber spatula to smooth tops, if necessary). Cut a cross slightly into the top of each bun using a sharp knife (or skip this step for smoother buns, using the glaze to draw the cross once cooled).
Set aside to rise in a warm area for 1 hour (on top of a preheating oven, or in an oven preheated to 200F, then turned off, is a good place to rise the buns). Once risen, brush buns with egg wash or milk of choice.
Preheat oven to 375 F (static) or 350F (convection).
Bake buns for 15 minutes; check for doneness with a toothpick. Remove to cool.
Whisk together the icing ingredients, taking care not to add too much liquid or the icing will drip all the way off the buns.
Once the buns are fully cooled, slowly spoon icing in a line across each cut of the cross on the top of the buns.