Step 1

Preheat the oven to 350 F. Spray an 8x8 or 9x9 pan with non-stick baking spray. Line with parchment paper and a sling if you want to easily be able to remove the bars from the pan for serving.

Step 2

In a large microwave-safe bowl, melt the butter and sugar for 1-1.5 minutes, then whisk to combine. The butter should be fully melted, the sugar starting to dissolve, and the mixture warm.

Step 3

Add the lemon juice, zest, eggs and yolk, and vanilla. Whisk vigorously for 30-40 seconds.

Step 4

Add the dry ingredients and stir with a rubber spatula until just combined. Don’t overmix.

Step 5

Pour into the prepared pan and bake for 20-25 minutes, until a toothpick comes out mostly clean. Cool completely.

Step 6

While cooling, combine the glaze ingredients in a small bowl with a whisk. Once the lemonies are cool, spread with the glaze. Slice and serve.