If you want to increase the calorie count you probably need to lean more on adding oil in your dishes.

I recommend walnut oil! It tastes great imo and has Omega 3 fatty acids. Keep it refrigerated for best flavor.

its not high calorie but for high protein I drink pea protein powder from Anthony's goods. it has 8g per tablespoon. for maintenance I have 1 80g shakeper day and for building I have 2.

its not filling so I have room for more calorie dense foods and don't need to think about protein content in the food I eat.

I don't have a good answer as I'm not vegan, but something to note of both tofu and seitan - seitan especially, it's that it's while it's theoretical protein is high, it's actual protein bioavailability is not that good unless it's supplemented with foods that have the right amino acid profiles to help absorb/break it down properly. Dr Mike has a good video on it. Watch from about 5 minutes in:

https://youtu.be/coRih_UvFQQ

Peanuts! although some evidence suggests people don't really gain weight. But peanut sauces added to beans/lentil bowls for more calories.

Nuts are proteiny and caloric, but very expensive.

If this was me, keeping in mind I don't know your sitch, I would go for soy based stuff that are mostly protein concentrates (tofu skin/bean curd sticks/tvp) and cook them with oily sauces I enjoyed. That way I could really focus on getting the fats and the protein for small and energetically dense meals, that said you would need to get some fibre elsewhere.

So like tofu skins braised in sesame or peanut sauce type stuff. Savoury tofu breakfast pudding with sesame oil.