Step 1 Combine 1/4 cup (60 mL) warm water, 1 tsp (5 mL) sugar and yeast. Let sit until foamy, about 5 to 10 minutes.
Step 2 Whisk whole wheat flour with 1 1/2 (375 mL) cups all-purpose flour, salt, cardamom, cinnamon, allspice and cloves; set aside.
Step 3 Whisk milk with butter, remaining sugar, egg, egg yolk, vanilla and lemon zest in a large bowl. Stir in yeast mixture. Stir in flour mixture with wooden spoon until shaggy dough starts to form, adding remaining all-purpose flour if dough is too sticky. Stir in raisins and candied peel.
Step 4 Transfer to lightly floured work surface and knead until smooth and elastic, about 10 minutes.
Step 5 Transfer to greased bowl. Cover and let rise until doubled in volume, about 45 to 60 minutes.
Step 6 Punch down dough. Turn out dough on lightly floured surface. Divide into 16 equal portions.
Step 7 Roll each portion, shaping into a ball. Place buns 1 1/2-inches (4 cm) apart on parchment paper-lined baking sheet. Let buns rise, covered, until doubled in volume, about 30 to 35 minutes.
Step 8 Preheat oven to 375°F (190°C). Bake buns in lower third of oven until golden brown, 15 to 18 minutes.
Step 1 Meanwhile, mix sugar with water in small saucepan set over medium high heat. Cook until sugar dissolves. Brush over buns. Cool buns completely.
Step 1 Mix icing sugar with yogurt. Add to re-sealable bag; snip corner. Pipe cross on top of each cooled bun.