The main characters are Erina and Soma. Erina is a highly skilled and refined chef with a discerning palate. Soma is a passionate and creative chef who often thinks outside the box. Their different personalities and cooking styles make their relationship in the fanfic very interesting.
One possible plotline could be them working together on a special menu for an important event at the school. They combine their unique cooking styles and skills, which leads to a new and amazing culinary creation.
One of the highly recommended ones might be 'A Taste of Love' which beautifully captures their relationship's growth. It delves deep into their emotions and how they come to understand their feelings for each other.
One common theme could be family. It might explore how Soma and Erina handle having a baby in terms of creating a family unit. Another theme could be growth. As they become parents, they may grow as individuals and in their relationship.
You can try some popular fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. They usually have a wide range of fanfictions, and you might be able to find ones related to Soma and Erina's love story there.
I haven't really delved into that particular 'soma x erina lemon fanfiction'. But usually, fanfiction communities on platforms like FanFiction.net could be a place to start. You can search for the pairing and then skim through the summaries to see if any catch your interest. Keep in mind that the quality can vary greatly.
I'm not certain about the common themes in 'soma x erina lemon fanfiction' precisely. However, in fanfiction about relationships, themes such as misunderstandings and reconciliations are often present. It's possible that in this pairing's fanfiction, their different cooking styles and how they complement or clash could be a theme. Also, family influence on their relationship might be explored.