Tomato sandwiches have the highest ceiling and the lowest floor. An out-of-season tomato slapped between two slices of sandwich bread is simply nothing to write home about, while a juicy, colorful tomato nestled between crusty bread is a peak summer meal for me.

The difference lies in the quality of ingredients and a thoughtful process. Because most people probably put less thought into their tomato sandwiches than yours truly, I did the dirty work for you and called up an expert to talk about tomato sandwiches—all in a day’s work.

Craig Lehoullier, a tomato farmer, author, and educator based in North Carolina with New England roots, knows what it takes to elevate a simple tomato sandwich into a sublime experience. Through years of cultivating tomatoes and experimenting with ingredients, Craig has honed the art of what I would consider the perfect tomato sandwich, or what he refers to as “summer heaven.”

The journey to an exceptional tomato sandwich begins with picking the right tomato at the right time. Craig recommends visiting a local farmer’s market or selecting heirloom varieties from a well-stocked grocery store for those looking to buy a tomato.

Craig’s absolute favorite variety for a tomato sandwich is a Cherokee Purple, and his next favorite options are yellow heirloom or beefsteak. He suggested avoiding tomatoes with cracks and never refrigerating them, as this diminishes their flavor and texture.

For those growing their tomatoes, Craig advises picking your tomatoes when they are halfway ripened rather than letting them become completely ripe on the vine. Craig reports, “Tomatoes that ripen on the vine, while delicious, are prone to cracking and are more likely to attract pests. Once you pick your half-ripe tomato, put it on your kitchen counter to complete the ripening process. Don’t put it on the sunny windowsill; certainly, do not store them in the fridge.”