oven roasted portobello mushroom burger w/ goat cheese & caramelized onions

yum. so today i made myself a yummy burger. it's vegetarian. a lot of times when you look for mushroom burger recipes, or spot 'mushroom burger' on a restaurant menu, you find that they're actually beef burger topped or stuffed with sauteed mushrooms. but i had an actual vegetarian portobello mushroom burger at cheesecake factory which was amazing, and although i didnt set out to recreate it today, i realized my creation tasted pretty similar!

as usual i skimmed a few recipes then did my thing. lately, ive been combining multiple recipes vs following one to the dot. i find it can be a great way to improve ones culinary skills

Again sorry about the vague quantities. Remember that the mushrooms cook down immensely, so you end up with maybe less than half of what you started with.

Ingredients

Portobello mushrooms (basically i bought a box of 8-9 portobellos. they werent as small as the baby sized ones, but maybe a size above. i originally wanted the largest ones they have, but alas)
Goat cheese (I used the one with herbs, mmm)
1 onion
1 tbsp sugar
Fresh minced garlic, a few cloves
Few tbsps olive oil
Few tbsps butter
Salt/pepper
Any mix of dried italian herbs. I used a blend with basil, oregano, rosemary, thyme, etc. Check the spices section at your local grocery store for 'italian seasonings'
Fresh baked bakery buns
French fries (optional)

Method:
Preheat oven to 350. Pull out the stems from the mushrooms and rinse lightly. Line on a baking sheet with the stem side facing up (so there is a nice opening to fill some herbs in). Melt one tbsp butter. Add one tbsp olive oil, garlic, 2 tbsp italian seasoning, salt and pepper to taste, mix. Using a spoon, fill the mixture into the mushroom opening generously. Make more of this mixture if you run out. Try to save a half tsp or so to use to saute the onions later. Cook the mushroom for 20-30 minutes or until they seem roasted to your liking. For a while they will seem soggy as the water dries up. I actually turned the mushrooms with the filling side facing down halfway into the cook time. Take them out of the oven when done and cool for 10 - 15 minutes, letting the juices and flavor soak in.

In a saucepan, melt some butter (or heat up some olive oil). Finely slice the onion, throw into pan, top with sugar and leftover italian seasoning + garlic mixture and cook on medium until caramelized. Cover the pan, remove from stove and let onions sit in  the heated pan. Add the cooled mushrooms to the heated pan and top both onions and mushrooms with goat cheese. Cover the pan again and let cheese melt in heat.

Toast the bakery buns and build burger with the mushroom-onion-cheese goodness. You may want to add more vegetables like lettuce and tomato if that's how you like your burgers, but this one tastes best on its own (to me, anyway). Serve with fries.