Betty,
I love the recipes in Cdn. Living Mag. I have a subscrption and also go to their site. Here is a recipe for "Crunchy-Top Blueberry Muffins", but the topping is sugar and Orange rind (zest). Perhaps it is the same recipe but they have now changed the Lemon to Orange.
Regards, Judy

CRUNCHY-TOP BLUEBERRY MUFFINS

2 cups all-purpose flour (500 mL)
3/4 cup granulated sugar (175 mL)
1 tbsp baking powder (15 mL)
1 tsp baking soda (5 mL)
1/2 tsp salt (2 mL)
1/2 cup plain yogurt (125 mL)
2 tsp grated orange rind (10 mL)
1/4 cup orange juice (50 mL)
1/4 cup vegetable oil (50 mL)
2 eggs
1 1/2 cups fresh blueberries (375 mL)
FOR THE CRUNCHY TOPPING:
1/4 cup granulated sugar (50 mL)
1 tbsp grated orange rind (15 mL)

Adjust oven rack to centre. Heat oven to 400 degrees F (200C). Line 12 muffin cups with paper liners.

Pour flour, sugar, baking powder, baking soda and salt into large bowl; whisk until blended.

Pour yogurt, orange rind and juice, oil and eggs into another large bowl; whisk until smooth. Pour yogurt mixture over dry ingredients. Sprinkle with blueberries. With wooden spoon, stir just until you can't see any flour. Spoon batter into prepared muffin cups, filling three-quarters full.

For the topping, in small bowl and using fingers or spoon, mix sugar with orange rind. Sprinkle over batter in each cup.

Bake muffins in oven until tops are golden and firm to the touch, about 25 minutes. Place rack on counter. Wearing oven mitts, transfer muffin tin to rack and let muffins cool.

Makes 12 muffins
Adapted from source: Canadian Living magazine: May 2006