Step 1In a small bowl, stir together the yeast, 1 teaspoon sugar and one-fourth cup warm water. Set aside until the yeast begins to foam, 5 to 10 minutes.
Step 2In a medium bowl, whisk together the 2 eggs, oil, rosewater or orange flower water, vanilla, remaining three-fourths cup warm water and salt.
Step 3In the bowl of a stand electric mixer fitted with a dough hook, place 4 1/2 cups (19.1 ounces) flour, sugar, fennel seeds, 3 tablespoons sesame seeds, raisins and grated peel if using. Mix briefly to combine. Make a well in the middle and add both the yeast and egg mixtures. Mix on medium-low speed, adding the remaining flour as necessary, and mixing until the dough leaves the sides of the bowl. Stop occasionally to scrape the sides of the bowl with a rubber spatula. The dough should still be slightly sticky. (The dough can also be mixed by hand; combine the ingredients and mix as listed above until the dough comes together, then knead; the dough will require additional kneading time.)
Step 4Transfer the dough to a lightly floured work surface and knead 5 minutes; the dough will be ready when it springs back quickly when poked. Place the dough in an oiled bowl, cover and set aside in a warm place until doubled in size, about 1 1/2 hours.
Step 5While the dough is rising, heat the oven to 350 degrees. Line a baking sheet with parchment paper. Punch down the dough and set aside for 5 minutes to rest. Divide the dough into 12 to 14 pieces, and roll each piece between the palms of the hand into smooth ovals the size of a piece of gefilte fish (about 3 inches long). Place the ovals onto the parchment-lined sheet leaving 1 1/2 to 2 inches between each (if your baking sheet is small, you may need to use 2).
Step 6In a small bowl, whisk together the remaining egg yolk with the honey, and brush this over each of the ovals. Sprinkle over the remaining sesame seeds and nigella (or black sesame seeds). Cover the ovals loosely with a piece of plastic wrap and set aside for 15 to 20 minutes to rise, then bake until golden-brown, about 25 minutes.