Prep the pan and oven: Preheat your oven to 350°F (175°C). Grease your mini Bundt pan very well with butter or baking spray, making sure to get into every ridge. If buttering, dust lightly with flour and tap out the excess.

Mix the lemon sugar: In a large bowl, combine granulated sugar and lemon zest. Use your fingers to rub the zest into the sugar until it smells fragrant and looks slightly damp. This step releases flavorful oils and boosts lemon taste.

Combine dry ingredients: To the lemon sugar, add flour, baking powder, baking soda, and salt. Whisk to blend.

Whisk wet ingredients: In a separate bowl or large measuring cup, whisk the eggs, oil, sour cream, milk, lemon juice, and vanilla until smooth and fully combined.

Make the batter: Pour the wet ingredients into the dry. Stir gently with a spatula until just combined. The batter should be smooth but don’t overmix; a few small lumps are okay.

Fill the molds: Spoon the batter into the prepared mini Bundt cavities, filling each about 2/3 to 3/4 full. Smooth the tops slightly for even baking.

Bake: Bake for 14–18 minutes, depending on your pan size. The cakes are done when the tops spring back and a toothpick comes out with a few moist crumbs.

Cool and release: Let the cakes cool in the pan for 8–10 minutes. Gently loosen edges with a small offset spatula or butter knife, then invert onto a wire rack. Cool completely before glazing.

Make the glaze: In a bowl, whisk powdered sugar, 2 tablespoons lemon juice, and a pinch of salt. Add milk 1 teaspoon at a time until the glaze is thick but pourable. You want it to slowly run down the sides, not disappear.

Glaze the cakes: Place a sheet of parchment under the rack. Spoon or drizzle glaze over each cake, letting it drip into the grooves. For a more opaque finish, let the first layer set for 5 minutes and repeat.

Set and serve: Allow glaze to set for 15–20 minutes. Enjoy at room temperature.