Lentil-Stuffed Portobello Mushrooms

For some reason I always underestimate how long it takes to cook lentils. I keep thinking they take 20 minutes, like white rice. They do not take 20 minutes. They take at least 30 and closer to 45. One time a large batch took an hour. An hour! For lentils! At any rate, two nights ago I happened to start dinner early, so it was okay that my lovely green organic lentils took their sweet time cooking. When they were finally ready, I mixed them with toasted walnuts, onion, garlic, and feta cheese to make a yummy filling for portobello mushroom caps.

Recipe after the jump.
Makes enough filling for two large mushroom caps

Portobello mushroom cap(s), stem and gills removed
1/2 c. green lentils
1/4 c. chopped walnuts, toasted (optional)
1 glove garlic, chopped
1 small onion, chopped
1 1/2 c. vegetable broth + more if needed
olive oil
salt & pepper
1/4 to 1/2 c. feta cheese

Preheat oven to 350-degrees F

Sort and rinse lentils and add to vegetable broth. Simmer covered until broth is absorbed and lentils are tender--30-45 min. Add more broth as necessary as lentils absorb it.

While lentils are cooking, toast walnuts if desired. Wash, stem, and remove gills from mushroom cap(s) (scrape out with a spoon). Place cap(s) bottom-up in a lightly oiled baking dish.

Chop onion and garlic. When lentils are nearly done, saute onion until it becomes translucent ~4 minutes. Stir in garlic and cook until fragrant--less than a minute. Combine onion, garlic, walnuts, lentils, feta, and salt & pepper (to taste) to make filling.

Heap filling onto mushroom cap and bake for about 20 min.

I'm not gonna lie--the filling was surprisingly good. Very flavorful. I hadn't thought to combine feta with lentils before, but it's a great combination and was well-complimented by the sautéed onion. I kept eating the extra out of the pan while the mushroom was cooking. I liked it so much in fact that I repurposed the leftovers in an excellent pot pie two nights later (post on that still to come). The filling was nice with the mushroom, but I think it's probably not strictly necessary to roast it all together. I think next time I'll roast the mushroom caps while the lentils are cooking, then just fill and serve. That would also save about 20 min.