Purée strawberries. Set aside.
In a small sauce pan put 3/4 cup of sugar and cover the sugar with a little bit of water until the sugar looks like wet sand. Cook on a stove top over high heat until it reaches 248 degrees (you will need a candy thermometer).
While the sugar is cooking, whip eggs whites in a bowl of an electric mixer fitted with the paddle attachment at a high speed until they reach soft peaks.
Once the egg whites reach soft peaks add the other 1/4 cup of sugar and mix on a high speed until the egg whites reach stiff peaks. You can keep mixing the egg whites at a high speed until the sugar is done cooking.
Once the sugar reaches 248 degrees immediately take it off the stove. While the mixer is still running on high speed, add the sugar syrup to the egg white mixture. Mix on a high speed for 30 minutes.
After 30 minutes, add the room temperature butter and mix on a high speed for 5-10 minutes until the butter is fully combined and the mixture resembles buttercream.
Add vanilla and strawberry purée. Mix until combined.
Add pink food coloring until you get desired color.