Preheat oven to 350°F and line one 12-cup muffin pan with paper liners or spray with cooking spray.

CRUMB TOPPING: Combine all ingredients until mixture resembles coarse crumbs. Set aside until ready to use.

FILLING: whisk together all ingredients until well combined. Set aside until ready to use.

MAKE THE MUFFINS: combine flour, sugar, baking powder, and salt in a large bowl. In a separate, smaller bowl, whisk together oil, egg, and milk. Pour wet ingredient mixture over dry ingredient mixture and stir with big wooden spoon until just combined.

Add 1 1/2 tablespoons of batter to each of the prepared muffin cups. Then, add 3/4 to 1 teaspoon (depending on how much you like cinnamon!) of the cinnamon swirl filling to the center of the batter. Top with a further 1 1/2 tablespoons of batter.

Cover muffins with crumb topping, then bake at 350°F for 15 to 20 minutes or until a toothpick inserted comes out clean.

Let cool in pan for a couple of minutes before carefully removing to a wire rack to cool utterly.

While they cool, whisk together the cream and powdered sugar to form a thick glaze. If too thick, add a bit more cream. If too thin, add more powdered sugar. Drizzle over top of cooled muffins.