Roast the beets. You'll likely need 2 medium beets. I wrap them in tinfoil, place on a baking sheet and bake for about an hour at 400 °F, or until you can easily stick a fork in them. I do this a couple hours before making the burgers so I can let the beets cool completely before shredding them.
Once the beets are roasted and cooled, peel them, and shred using a box grater. You'll need 1 cup packed. You can squeeze some of the water out, but it's not necessary.
In a large bowl, add the shredded beets, lentils, oats and spices. Using your hand (or a fork) combine everything really well. Make sure to squeeze and break apart most of the lentils. The mixture should hold together really well.
Cover the bowl, with a dish towel or saran wrap, and place in the fridge for about 30 minutes. This allows time for the oats to soak up any liquid.
After 30 minutes, you can shape your burgers. Using about 1/3 cup of lentil mix, shape into patty form. It should make about 4-5 burgers.
Place a large frying pan over medium heat, add 1 Tbsp olive oil (or a cooking spray). Once the pan is hot, add your burgers. Cook for about 3-4 minutes per side, or until golden brown.
Enjoy on a bun with your favourite burger toppings!