I make a meat option for those who want it, and extra veggies for the rest of us.

Polenta with sautéed mushrooms, meatballs in sauce, green beans on the side

Baked potatoes topped with broccoli and cheese for half of us, chili for the others

Small dish of eggplant parm, small dish of chicken parm

Veggie fried rice, stirfry chicken separately and add for those who want it

Make vegetarian chili and pan fry chicken thighs on the side

Sheet pan roasted veggies, separate pan with meat of choice, salad with nuts and cheese

We’re omnivores but do go veggie a few times a week. These have all bee received well. I also make a lot of roasted vegetables rice bowls with a few different homeade quick pickles, adding a tahini miso sauce. You can use sweet potatoes in place of rice, quinoa, or grains; or a small portion of each as base.

Moosewood Cookbooks Mousska is delicious and filling. You can adjust the veg a bit if not into mushrooms or eggplant. https://www.saveur.com/article/Recipes/Mushroom-Moussaka/

BBQ tofu is also really yummy. This is a sheet pan version. I use high protein extra firm tofu and find baking time sweet spot is between 25-30 mins for crispy but soft inside or 30+ mins for crispy/chewier. You can also adapt this by changing rub spices or sauce.
https://www.thekitchn.com/sheet-pan-bbq-tofu-recipe-256176#post-recipe-12562


Also super good.

https://smittenkitchen.com/2013/05/japanese-cabbage-and-vegetable-pancakes/

Chili - one with meat, one with extra beans. You could follow the same basic recipe.

Make your own bowl / taco. Tortilla, beans, cheese, meat, salsa, cheese, etc.

Pasta of any type with a meat on the side.

Make your own pizza - buy both veg and meat options.

Burgers / veg burgers

Stir fry - but stir fry meat separately. They can add it in.

Try a cookbook like this one. There are a bunch. It shows you how to make one meal, that can easily be made meat or veggie for different family members. https://www.amazon.com/dp/1981674187/ref=cm_sw_em_r_mt_dp_YQJ34RN23G1T4FAQGNKK

I just discovered the Bob’s Red Mill bean soup mixes. They are fantastic by themselves or as a base for something more elaborate, and so easy to make in the instant pot. You can use water or a veg broth to cook, and add shredded chicken or cooked sausage to the non-vegetarian bowls if you need more protein.

We do make your own tacos every week in my house. We always have:

Soft flour tortillas
Black beans
Yellow rice
Salsa
Guacamole
Avocado
Shredded cheddar
Chopped tomatoes (usually sweet orange)

Additionally, we usually have some combo of the following:

Hard corn tortillas
Corn
Refried beans
Sour cream
Another type of shredded cheese (Mexican blend, pepper jack)
Sauteed zucchini or mushrooms
Ground chicken or beef or grilled chicken or shrimp

We are all eating together but we all put together a very different meal for ourselves.

I’m in the opposite situation: my young kids don’t eat meat (although they love shrimp) but I’m nursing and get lightheaded without animal protein once a day. Some things I make:
Veg fried rice (egg protein for kids) with pre-cooked chicken added after I’ve put aside kid portions
Lentils or chickpeas and couscous (+added chicken protein boost)
Pizza bagels (pepperoni or sausage for meat eaters, plain veg for vegetarians)
Tofu (or shrimp for us) curry or in a rice bowl with veg and peanut sauce
Macaroni and cheese with peas or broccoli, throw in chicken or sandwich steak for anyone craving meat
Tacos or burritos with veg refried beans and/or avocados on offer as well as taco meat

I would note that your young athlete may also be craving healthy fats that come in meat too so vegetarian and vegan offerings with those included (eg veg curry with coconut milk, peanut sauces, anything with avocado, vegetarian refried beans, etc) may help keep them full without meat at every meal.

My family is like this and we end up doing a lot of things like pizza, tacos, pasta, burgers/patties - things that it's easy to do a combo of meat/no meat.

Black bean nachos or quesadillas. Baked ziti type meal but use beefless beef crumbles instead of meat. I am a vegetarian, spouse is not. Spouse says they would think it was beef if I hadn’t told them different.

The easiest thing to do grain bowls. My bowl will have quinoa, kale, sweet potatoes, bell peppers, etc -- meat eater will have all that plus chicken, etc. This is the business model for salad places like Sweet Green, Chop't, Cava Grill, Chipotle, etc.

Are you opposed to cooking meat yourself? Tacos are easy to do veggie and meat separately and everyone assembles their own. You can do a pasta and brown some meat to mix into the sauce for your son.

Chili - I use quinoa instead of ground beef
Tacos - I use Lentils
Stuffed Peppers - Again lentils or quinoa
Rataouille _ put over rice or quinoa

Research Indian vegan or vegetarian recipes. They have tons!

- Enchilladas and tacos. Make some vegan and some meat ones.
- Pasta dishes- make a vegan base + have meat sauce/meatballs to add - Stir fries- make with veges + have side chicken, pork, shrimp
- soup- vege base + have shrimp, crab, etc. On side
It is not that hard OP

Spinach and cheese ravioli, salad.
Try tofo marinated and grilled.

I am the sole vegetarian in our house these days. I've been trying to come up with dinners that please everybody. My son is an athlete and craves meat. He's often not very satisfied with the vegan meals I prefer so DH will often cook some chicken, fish, or (occasionally) pork or beef and add it to their plates at least a 3-4 times a week -- sometimes it works well; others not so well.

Lunch and breakfast are much easier -- I can make a mean omelet with cheese & greens with a side of toast and fruit, and my son is 100% satiated with energy for the full morning.

Anyone else planning and cooking dinners like this? Any suggestions for meals that can easily transition from vegan (or vegetarian, some dairy & eggs are ok) to having a meat-based protein added without it getting boring?