Add the sauce ingredients to a pot over medium-high heat: dijon mustard, whole grain mustard, brown sugar, honey, cooking oil, and white vinegar. Heat slowly stirring often for 2 minutes, until sugar melts.
Remove from heat and add the fresh thyme.
Add the ham to a large roasting pan. Drizzle the mustard thyme glaze over top. Bake for 1 hour, basting the ham once or twice during the process (see notes for how long to cook).
Remove from dish and place on serving plate. Slice and serve. Any remaining glaze can be spooned onto the ham. Or added to rice, quinoa or pasta.
Glaze measurements works best for 1 medium-sized fully cooked ham, but will also work for small and large.
Smaller ham (1.5 lbs) can be baked for 1 hour-ish or until warmed through (use extra sauce on rice, quinoa or pasta served with ham).
Medium to large ham (4-7 lbs) can be baked for 1 hour 15 minutes or until warmed through.