Whisk together all the ingredients for the dressing: the shallot, mayo, mustard, olive oil, apple cider vinegar, maple syrup, lemon juice, milk and poppyseeds. I usually start with 3 tablespoons of milk and add another if the dressing is too thick. Taste, adjusting seasoning as needed-- I find that the mayo is salty enough, but you can add a little salt as desired.
Make the Salad
In a large bowl, toss together the spinach leaves, strawberries, blueberries, pecan and feta.
Add the dressing and toss well, taste, adjust seasonings, and serve immedietly.
Notes
To make dairy-free, use vegan mayo of choice and unsweetened milk.