Preheat the oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper, leaving overhang on the long sides for easy lifting, and lightly grease the parchment and sides of the pan.

In a large mixing bowl, beat the softened butter and granulated sugar together with a stand mixer or hand mixer on medium speed for 2–3 minutes, until light and fluffy and slightly pale in color.

Add the eggs one at a time, beating well after each addition and scraping down the bowl as needed. Mix in 1 1/2 teaspoons vanilla extract and 1/2 teaspoon almond extract (if using) until the mixture looks smooth and glossy.

In a separate bowl, whisk together the flour, fine sea salt, and baking powder until well combined and no clumps remain.

Add the dry ingredients to the wet mixture in two additions, mixing on low speed just until combined after each addition. The dough will be thick but spreadable, similar to a soft cookie dough. Avoid overmixing once no streaks of flour remain.

Transfer about two-thirds of the dough into the prepared pan. Use a spatula or lightly dampened fingers to press it evenly over the bottom of the pan, forming a level crust.

In a medium bowl, combine the cherry pie filling, lemon juice, and 1/4 teaspoon almond extract (if using). Stir gently to blend without breaking up the cherries too much. Taste and add a bit more lemon juice if you prefer a brighter flavor.

Spread the cherry filling evenly over the pressed crust, all the way to the edges, so each bar gets a good amount of fruit.

Using the remaining one-third of the dough, drop small spoonfuls randomly over the cherry layer. Do not cover the cherries completely—leave some spots exposed so the filling can bubble through as it bakes.

Bake in the preheated oven for 35–40 minutes, until the top is lightly golden and the edges are set. The center should no longer look wet, though it may still jiggle slightly; it will firm up as it cools. If your oven runs hot, start checking around 30 minutes.

Transfer the pan to a wire rack and let the bars cool completely in the pan, at least 1–2 hours. This helps the filling set and allows for clean slices.

Once the bars are cool, whisk together the powdered sugar, 1 tablespoon of milk or half-and-half, vanilla extract, and a pinch of salt in a small bowl until smooth. If the glaze is too thick, add more milk a teaspoon at a time until it is pourable but not runny.

Drizzle the glaze over the cooled bars in a zig-zag or crosshatch pattern. Let the glaze set for about 15 minutes, then use the parchment overhang to lift the slab out of the pan. Slice into 20–24 squares, wiping the knife between cuts for the neatest edges.