Rainbow Cookies Recipe

Prepare and preheat

Preheat the oven to 350°F (175°C). Line a 9x13-inch (or two 9x9) baking sheet with parchment paper, leaving an overhang for easy removal. Lightly grease the parchment.

Cream butter and sugar

In a large bowl, cream 1/2 cup softened butter with 1/2 cup granulated sugar until pale and fluffy, about 3–4 minutes with a hand or stand mixer on medium speed.

Incorporate yolks and extracts

Add the 4 egg yolks one at a time, mixing well after each addition. Beat in 1 tsp vanilla extract and 1 tsp almond extract until combined.

Combine dry ingredients

In a separate bowl whisk together 1 cup all-purpose flour, 1/2 cup ground almonds, 1/2 tsp baking powder, and 1/4 tsp salt. Gradually fold the dry ingredients into the butter mixture until just combined.

Whip egg whites

In a clean bowl, whip 4 egg whites with 1/8 tsp cream of tartar until soft peaks form. Gradually add 1/4 cup powdered sugar and continue whipping to glossy stiff peaks.

Fold whites into batter

Gently fold about one-third of the whipped egg whites into the batter to loosen it, then fold in the remaining whites carefully to retain air. The batter should be light and spreadable.

Divide and color batter

Divide the batter into three equal portions (about 1 1/3 cups each). Keep one portion plain. Tint the second portion with red food coloring (start with a few drops and add until you reach a pale pink to red). Tint the third portion with green (or another color) until desired shade is reached.

Bake layers

Working one color at a time, spread each portion into a roughly 9x13-inch rectangle on the prepared pan (or use two pans and bake separately). For neat layers, spread each color in a thin, even layer about 1/4-inch thick. Bake 6–9 minutes until the top springs back slightly and edges pull away; do not overbake. If you must bake colors separately, allow the first layer to cool slightly before lining the pan again for the next color.

Cool and trim

Remove the baked sponges to a wire rack. While still slightly warm, cover with a clean kitchen towel to keep them pliable. Once cooled, trim the edges so all three layers are the same size and stackable. (If you baked in the same pan sequentially, you can stack directly after cooling between layers.)

Prepare filling

In a bowl, beat 1/4 cup softened butter until smooth. Add 1/2 cup powdered sugar, 3/4 cup seedless raspberry jam, and 1/2 tsp lemon juice. Beat until smooth and spreadable. Taste and adjust sweetness with extra powdered sugar if needed.

Assemble cookie stack

Place one almond sponge layer (plain or chosen color) on a flat surface, cut to 6 equal rectangles (about 3 equal rows x 2 columns) if not yet portioned. Spread a thin, even layer (about 2–3 tbsp) of the raspberry filling across the surface. Top with the second sponge layer and repeat with another thin layer of filling. Place the third sponge layer on top and press gently to adhere. Chill the stacked sponge in the refrigerator for 15–20 minutes to firm up for easier cutting.

Portion into cookies

Using a sharp knife or bench scraper, trim edges for neatness if needed, then cut the stacked cake into 6 equal rectangular cookies. Place pieces on a parchment-lined baking sheet and chill again briefly so they hold their shape for dipping.

Melt chocolate

Place 5 oz semisweet chocolate and 1 tsp vegetable oil in a heatproof bowl. Melt gently using a double boiler (simmer water, bowl over but not touching water) or microwave in 20-second bursts, stirring between bursts, until smooth. Do not overheat.

Coat cookies

Remove cookie portions from the fridge. Holding a cookie by the long edge with a fork or dipping tool, dip each cookie halfway into the melted chocolate so the top and sides are coated about halfway up. Allow excess chocolate to drip back into the bowl, then transfer to a parchment-lined sheet. If preferred, pour chocolate over the center of each cookie and spread to the edges for a top-only coat.

Set and finish

Let the chocolate set at room temperature (about 30–45 minutes) or speed up by chilling for 10–15 minutes. Once set, if desired, dust the exposed almond sponge edges with a light dusting of powdered sugar for a finished look. Store cookies in an airtight container in the refrigerator for up to 5 days; bring to room temperature before serving for best texture.