I have a question about the recipe "Judy Rodgers' Lentils Braised in Red Wine" from Nicholas Day. Lentils never soften; don't cook fully
A few ideas (maybe not news):
Look at serious eats for an article about how salting helps beans cook better.
If you have trouble getting the lentils to the consistency you want, cook them longer.
Or replace them with a bean whose texture after cooking you like better.
Maybe the lentils is old? It happens to me on other recipes when I accidentally cook old lentils.
Are you using the "de Puy type" lentils (a.k.a. French Green lentils) mentioned in the ingredient list? That particular type of lentil doesn't soften completely like other types; rather, it holds its shape and still has a bit of "tooth" to it.
If you prefer something that will soften more, you could try regular brown or green lentils for a different, but no doubt delicious, result.