Place the larger amount of strawberry jam into a piping bag fitted with a coupler and a #12 piping tip.
Place the strawberry buttercream in a piping bag fitted with a coupler and a #12 piping tip.
Flip half of the macaron shells upside down and pipe a ring of buttercream around the outside of the macaron (i.e., on the flat part of the cookie). Fill the center of the buttercream ring with strawberry jam. On some of my larger cookies, I did a double bullseye so there would be a little more strawberry jam.
Place the other half of the cookie on the filling and gently press to push the filling to the edge of the cookie.