SLOW COOKER BROCCOLI CHEESE SOUP

Ingredients
1/3 cup butter, sliced
1 1/2 cups chopped yellow onion
2 cloves garlic, minced
6 Tbsp almond flour
Salt and freshly ground black pepper
2 (12 oz) cans evaporated almond milk
5 cups low-sodium chicken broth
5 cups small diced broccoli florets*
1/8 tsp dried thyme
1/2 cup heavy cream
12 oz sharp cheddar cheese, freshly shredded (or more to taste)
2 oz parmesan cheese, freshly & finely shredded