_{Serat Centhini jilid ketiga, yang menggambarkan perjalanan Cebolang dari candi Prambanan menuju Pajang, mampir di dusun Tembayat wilayah Kabupaten Klaten dan dijamu makan siang oleh Pangeran Bayat dengan lauk seadanya: "…brambang jae santen tempe … asem sambel lethokan …" sambel lethok dibuat dengan bahan dasar tempe yang telah mengalami fermentasi lanjut. Pada jilid 12 kedelai dan tempe disebut bersamaan: "…kadhele tempe srundengan…"}
Serat Centhini in Chapter III, which describes Cebolang's journey from Prambanan temple to Pajang, stopped at the small village, Tembayat, Klaten Regency, and was treated to lunch by Prince Bayat with simple side dishes: "…brambang jae santen tempe… asem sambel lethokan …" lethokan sauce was made with basic ingredients of tempeh that had undergone further fermentation. In Chapter 12, soybeans and tempeh are called together:"... "…kadhele tempe srundengan…"
Serat Centhini was written in Javanese letters or alphabets by Kyai Ngabehi Ranggasusastra, in 1814 and finished in 1823.
https://kebudayaan.kemdikbud.go.id/bpnbyogyakarta/serat-centhini-karya-besar-sastra-jawa-lama/
That is the basis of literature from an ancient book about tempeh.

There are some researchers who believe tempeh originated in China. Yet, In the past, Chinese people in Java used soy beans to make tofu but they did not make tempeh.
Tempeh was made by the lower class Javanese people, not by the royal and upper middle classes. In Serat Centhini, when treating Cebolang (a royal family of the Javanese Kingdom), Pangeran Bayat served him with simple side dish.
Tempeh is made of fermented soybeans, or kedele. The inventor of tempeh is Anonimous. It is like bitcoin, haha lol. In Java, the fungus used to make tempeh is called Kapang.

During the Dutch colonial period, forced cultivation regulations made foodstuffs such as tempeh very vital as a savior for the health of the population in Java. The Javanese people found it increasingly difficult to get meat from fish in rivers, game and livestock during the Dutch colonial period.

Tempeh contains excellent nutrition that equals meat.

Tempeh is a versatile ingredient that comes with a variety of health benefits. It’s high in protein, prebiotics, and a wide array of vitamins and minerals.
https://www.healthline.com/nutrition/tempeh

Bangsa Tempe and Mental Tempe

So in Java, the terms "Tempeh Nation" and "Tempeh Mentality" are used to mock the lower class Javanese people.It is because the lower class people are raised on the cheap nutrition source "tempeh".
http://www.komunitashistoria.com/article/2015/07/07/sejarah-tempe/
However, tempeh is massively produced in all major cities in Indonesia today. The producers are not only Javanese people but also other ethnic groups.

Various processed tempeh

Tempeh can be processed into many kinds of dishes like chips, mendoan, boiled tempeh, coated fried tempeh, and others.

Pic : https://www.loveusaha.com/berita/keripik-tempe-khas-malang/

Pic ; https://bosresep.blogspot.com/2017/01/resep-mendoan-khas-banyumas.html
Tempeh is a nutritius dish that can be made into some variants. Tempeh has an old history of human civilization.