1-Brown the butter: Melt 1 cup unsalted butter over medium heat in a saucepan, swirling occasionally until foaming and golden brown solids form. Scrape the browned butter and bits into a mixing bowl and let it cool for 30 minutes at room temperature.

2-Mix in sweeteners: Add ⅔ cup granulated sugar, ⅔ cup dark brown sugar (lightly packed), and 2 teaspoons molasses to the butter, then mix well.

3-Add eggs and vanilla: Beat in 2 large eggs and 2 teaspoons vanilla extract until the mixture is smooth and ribbon-like.

4-Combine dry ingredients: In a separate bowl, combine 2 cups all-purpose flour (spooned and leveled), 2 cups old-fashioned oats, 2 teaspoons coarse Kosher salt (or half if using table salt), 1 teaspoon baking soda, 2 teaspoons ground cinnamon, ¼ teaspoon ground cloves, ¼ teaspoon ground ginger, and ¼ teaspoon ground nutmeg.

5-Mix everything together: Mix the dry ingredients into the wet ingredients until fully combined.

Divide the dough into 20 portions, shaping each into a ball. This step ensures uniformly sized cookies that bake evenly. Place the dough balls in the refrigerator and chill for 20 minutes. This chilling period is crucial as it helps prevent excessive spreading during baking, which can be more pronounced at high altitudes.

Preheat the oven to 350 degrees Fahrenheit and position the rack in the center, lining a baking sheet with parchment paper.

Place the chilled dough balls 3 inches apart on the baking sheet to allow for spreading.

Bake for exactly 8 minutes, until the edges are set with a light golden color while the center remains gooey. This precise baking time is essential for the soft texture that characterizes these cookies.

Immediately after baking, use a round cookie cutter slightly larger than the cookies to gently shape the edges.

Cool the cookies on the baking sheet for 2 minutes, then transfer to a cooling rack until completely cool.

Beat 1 cup unsalted butter (softened to room temperature), 2 cups powdered sugar, 1½ teaspoons meringue powder (if using), and 1 teaspoon vanilla extract until light and fluffy.

The meringue powder is optional but highly recommended as it helps stabilize the filling, giving it a better texture and preventing it from becoming too soft.

Once the cookies have completely cooled, it’s time to assemble your treats. Pair the cookies, turn half of them over, and pipe a thick layer of the buttercream onto the bottom halves. Sandwich them together with the remaining cookies and press gently. For perfect presentation, use a large piping tip (such as 6B) to create a professional-looking swirl of filling, or simply spread it thickly with a spatula.