Make cake: Preheat oven to 350°F with rack in middle. Butter cake pan.
Whisk together flour, baking powder, salt, and spices.
Beat together sugar, oil, eggs, and vanilla with an electric mixer until combined well.
At low speed, mix in pears and cranberries, then mix in flour mixture until incorporated.
Spoon batter into pan.
Bake until a wooden pick inserted into center of cake comes out clean, 1 1/4 to 1 1/2 hours.
Cool in pan 30 minutes, then turn out onto a rack and cool completely.
Make glaze: Bring cream, brown sugar, corn syrup, vanilla, cinnamon sticks, and a pinch of salt to a boil in a small heavy saucepan, stirring occasionally, then simmer until slightly thickened, about 10 minutes.
Cool glaze 5 minutes. Discard cinnamon sticks, then pour glaze over cake, letting some drip down sides.
Cooks' notes: Cake, without glaze, can be made 1 day ahead and kept at room temperature. Cake can be glazed 3 hours ahead.