Preheat oven to 375ºF and coat a 12-hole muffin tin with cooking spray (or muffin liners).
Core and chop pears into tiny cubes; place in a large bowl. Add cinnamon, granulated sugar and lemon juice to pears; gently stir and set aside.
In a small bowl, whisk together sour cream, egg, 1 teaspoon vanilla and milk; set aside.
In a large bowl, sift together flour, baking powder, baking soda and salt.
Make a well with a spoon in center of flour mixture and pour in sour cream mixture and fruit mixture, alternating in small batches; mix until barely blended. Do not over beat. (NOTE: Batter will be very thick.)
Drop batter into prepared muffin holes until about 2/3 to 3/4 full; bake until tops are golden, about 30 to 35 minutes. Remove from oven and cool for 5 minutes in muffin pan; remove from pan to a wire rack to cool completely. (Or leave slightly warm to dip into glaze for easier preparation.)
While muffins are cooling, make glaze: Mix together powdered sugar, ginger, remaining 1/4 teaspoon vanilla and warm water in a small bowl (add another teaspoon of water if glaze is too thick). Spread a thin layer of glaze over each muffin. Yields 1 muffin per serving.
