My mother (in England) has a Belling Microwave before 1979.
https://en.wikipedia.org/wiki/Nicholas_Kurti
In
1969 he gave a talk at the Royal Society titled "The physicist in the kitchen", in which he amazed the audience by using the recently invented microwave oven to make a "reverse Baked Alaska", aka Frozen Florida (cold outside, hot inside).
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I recommend two cookbooks (paper only) both available used at minimal prices
Microwave Gourmet Sep 1987 by
Barbara Kafka
https://www.amazon.com/Microwave-Gou...dp/068806843X/
Microwave Gourmet Healthstyle Cookbook by
Barbara Kafka
https://www.amazon.com/Microwave-Gou...dp/068807572X/