This tender, moist, lemon coffee cake offers a triple threat of citrus flavor. The dense pound cake base and buttery crumble topping are delicately zesty, while the sweet glaze packs a tart, lemony punch.
Preheat the oven to 350°F. Grease a tube pan, or a 9" x 13" pan.
To make the streusel: Stir together the dry ingredients. Cut in the cold butter until the mixture is crumbly, then stir in the grated rind and pecans. Set aside.
To make the cake: Sift together the flour, baking powder, salt, lemon powder (or zest), and cinnamon. Set aside.
Beat the butter, sugar and lemon oil together until smooth and light. Add the eggs, one at a time, mixing until each is absorbed before adding the next. Mix in half of the dry ingredients. Scrape down the bowl, then add the sour cream and mix until combined. Add the remaining dry ingredients, mixing just until incorporated.
Transfer the batter to the prepared pan and smooth the top. Sprinkle the streusel evenly over the batter.
Bake the lemon coffee cake for 33 to 38 minutes for a 9" x 13" pan or 40 to 45 minutes for a tube pan, until a paring knife inserted in the center comes out clean. Remove from the oven and let cool in the pan on a rack for 10 minutes. To turn out of the tube pan, put a plate over the top of the pan and flip the cake over. Remove the pan, then flip upright onto a serving plate.
To make the glaze: Whisk the lemon juice and confectioners' sugar together; drizzle over the cooled lemon coffee cake. Slice and serve at room temperature.
Storage information: Store leftover lemon coffee cake, well-wrapped, on the counter for up to 3 days; freeze for longer storage.
