Start each line in the table with a “|” (and optional: end it with a pipe also):
| This is a | Table
| – | –
| col1 | col2
| giraffe | tall
| | the first cell should be blank
| \ | the first cell should be blank
| The second cell is blank |
Result:
| This is a |
Table |
| col1 |
col2 |
| giraffe |
tall |
|
the first cell should be blank |
| \ |
the first cell should be blank |
| The second cell is blank |
|