1. In small saucepan set over low heat, cook milk for 3 to 5 minutes or until milk is warm (120ºF to 130ºF/50ºC to 55ºC on instant-read thermometer). Add yeast; let stand for about 10 minutes or until bubbles form on surface.
2. In bowl of stand mixer fitted with dough hook attachment, mix all-purpose flour, bread flour, bread booster, sugar, cinnamon, allspice, nutmeg, cloves and salt on low speed. Mix in condensed milk and orange zest.
3. Mix dough on low speed until ball of dough starts to form and pulls away from side of bowl. Add butter, 1 tbsp. (15 mL) at a time, until incorporated.
4. Transfer dough to lightly floured work surface; knead in raisins. Knead for 6 to 8 minutes or until smooth and elastic, and dough springs back when lightly pressed with 2 fingers. Cover with tea towel; let stand for 10 minutes.
5. Divide dough into 9 portions. Shape each portion into ball. Place buns on 9-inch square parchment paper–lined baking pan, about 1 inch (2.5 cm) apart. Cover with tea towel; let stand for 40 to 45 minutes or until doubled in size.
6. Topping: In small bowl, stir together flour, 3 tbsp. (45 mL) water, oil and salt until consistency of thick paste. Spoon into piping bag fitted with small round tip. (Alternatively, spoon into resealable plastic bag with bottom corner snipped.) Using small, sharp, floured knife, score cross in top of each bun. Pipe paste into scored crosses.
7. Preheat oven to 350?F (180?C). Bake for 25 to 30 minutes or until golden brown and buns sound hollow when tapped. While still hot, brush with butter. Let cool completely on rack.

Tips:

Substitute currants or mixed dried peel for Sultana raisins if desired.

Substitute apricot jam or jelly for melted butter in the topping if desired. Heat jam in small pan set over medium heat until melted and runny. Strain mixture before brushing over buns.