Preheat oven to 325F. Prepare 3 baking sheets lined with parchment paper. If desired, draw circle guides on the back of the parchment paper for guides; set aside.

Prepare the dry ingredients. Measure out the almond flour and confectioner's sugar. When measuring in cups, do not pack the ingredients into the measuring cup, spoon in the ingredients! Place the flour and sugar into a food processor and pulse for a few minutes until the two are well combined. Sift the mixture through a fine-mesh strainer into a large bowl. If any almond pieces remain, return them to the food processor and pulse again, then sift again.

Prepare the meringue. Place the egg whites into a very clean mixing bowl. Add the sugar. Mix on high speed until stiff, glossy peaks form. The egg whites should stick to your whisk attachment when lifted from the bowl.

Mix the cookie batter. Add the strawberry emulsion and gel color to your mixing bowl. Add the sifted dry ingredients. Using a large spatula, begin folding the meringue and flour together. Scrape from the bottom of the bowl and press the ingredients against the sides of the mixing bowl to deflate the meringue. Continue folding and mixing until batter reaches the consistency of thick lava; the batter should ribbon off the spatula and settle back down into the bowl.

Transfer the batter into a pastry bag. Pipe small dollops onto the parchment paper, spacing the cookies about 1 inch apart. To rid the batter of air bubbles, tap the pan hard against counter top lined with towel. Let cookies stand at room temperature for 30 to 60 minutes, allowing the cookies to form a thin outer "shell". The time will depend on your local humidity (you can check your local weather channel for humidity levels; these cookies work best on low humidity days!).

Bake cookies in preheated oven for 12-14 minutes. Each oven bakes differently, watch the first pan carefully. If cookies are browning, your oven is too hot, turn it down by 5 to 10 degrees.

Remove cookies from oven and cool on parchment paper, then transfer to wire rack. Cookies should lift off of the parchment paper with no resistance. If they are stuck, this means your cookies are still raw and didn't finish baking.

Prepare the buttercream. Place softened butter into mixer bowl and whisk until light, fluffy and white in color. Add the sweetened condensed milk, extract and confectioner's sugar. Whisk for another 5 to 7 minutes until light and fluffy. (note: this recipe makes extra frosting which can be used for another batch of cookies)

Turn half of the cookies over and pipe a generous amount of filling onto each cookie, leaving the center empty. Into the center, pipe a small dollop of strawberry preserves. Sandwich the cookies with an empty half.

Store the cookies in an airtight and sealed container in the refrigerator. Take them out about 1 hour prior to serving to allow the buttercream to thaw. This recipes makes about 20 medium-sized macarons.